System and method for time domain grant-free pusch resource allocation

ABSTRACT

A user equipment (UE) may determine that a transmission resource includes a first orthogonal frequency-division multiplexing (OFDM) symbol that is configured as a downlink symbol or as flexible, where the transmission resource is allocated for uplink (UL) transmissions during a time duration, and includes K transmission occasions (TOs). The UE may transmit a first UL transmission in the transmission resource omitting the first OFDM symbol. The first UL transmission includes K repetitions to be transmitted in the respective K TOs, and the K repetitions includes an initial transmission and at least one retransmission of the initial transmission.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/621,036, filed on Jan. 23, 2018, which application is herebyincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to wireless communications, andin particular embodiments, to a system and method for time domaingrant-free physical uplink shared channel (PUSCH) resource allocation.

BACKGROUND

In some wireless communication systems, an electronic device (ED), e.g.a user equipment (UE), wirelessly communicates with a Transmission andReceive Point (TRP), termed “base station”, to send data to the EDand/or receive data from the ED. A wireless communication from an ED toa base station is referred to as an uplink communication. A wirelesscommunication from a base station to an ED is referred to as a downlinkcommunication.

Resources are required to perform uplink and downlink communications.For example, an ED may wirelessly transmit data to a base station in anuplink transmission at a particular frequency and/or during a particularslot in time. The frequency and time slot used are examples ofresources.

In some wireless communication systems, if a UE wants to transmit datato a base station, the UE requests uplink resources from the basestation. The base station grants the uplink resources, and then the UEsends the uplink transmission using the granted uplink resources. Anexample of uplink resources that may be granted by the base station is aset of time-frequency locations in an uplink orthogonalfrequency-division multiple access (OFDMA) frame.

The base station is aware of the identity of the UE sending the uplinktransmission using the granted uplink resources, because the basestation specifically granted those uplink resources to that UE. However,there may be schemes in which the base station does not know which UE,if any, is going to send an uplink transmission using certain uplinkresources. An example is a grant-free uplink transmission scheme inwhich UEs may send uplink transmissions using certain uplink resourcesshared by the UEs, without specifically requesting use of the resourcesand without specifically being granted the resources by the basestation. The base station will therefore not know which UE, if any, isgoing to send a grant-free uplink transmission using the resources.

In an LTE grant-based transmission, the required transmission parametersare typically communicated via a Physical Uplink Control Channel (PUCCH)and/or Physical Downlink Control Channel (PDCCH). The base station isaware of the identity of the ED sending the uplink transmission usingthe granted uplink resources, because the base station specificallygranted those uplink resources to that ED. In a grant-free transmission,different EDs may send uplink transmissions using uplink resourcesshared by the EDs, without specifically requesting use of the resourcesand without specifically being granted the resources by the basestation. One advantage of grant-free transmission is low latencyresulting from not having to request and receive a grant for anallocated time slot from the base station. Furthermore, in a grant-freetransmission, the scheduling overhead may be reduced. However, the basestation does not have information which ED, if any, is sending agrant-free uplink transmission at a particular moment of time, which mayrequire blind detection of grant-free transmissions received at the basestation. In other words, the base station is required to determine whichED is transmitting.

SUMMARY

Technical advantages are generally achieved by embodiments of thisdisclosure which describe a system and method for time domain grant-freephysical uplink shared channel (PUSCH) resource allocation.

In accordance with one aspect of the present disclosure, a method isprovided for wireless communications. The method includes determining,by a user equipment (UE), that a transmission resource includes a firstorthogonal frequency-division multiplexing (OFDM) symbol that isconfigured as a downlink symbol or as flexible, where the transmissionresource is allocated for uplink (UL) transmissions during a timeduration, and includes K transmission occasions (TOs), and K is aninteger greater than 1. The method further includes transmitting, by theUE, a first UL transmission in the transmission resource omitting thefirst OFDM symbol. The first UL transmission includes K repetitions tobe transmitted in the respective K TOs, and the K repetitions include aninitial transmission and at least one retransmission of the initialtransmission.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured for a downlink (DL) transmission.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured as flexible and dynamically configured asflexible.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured as flexible and dynamically configured for DLtransmission.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured by a higher-layer parameter comprising a timedivision duplex (TDD) UL-DL configuration common parameter or TDD UL-DLconfiguration dedicated parameter.

Optionally, in any of the preceding aspects, the K TOs are located in Krespective slots.

Optionally, in any of the preceding aspects, transmitting the first ULtransmission in the transmission resource omitting the first OFDM symbolcomprises transmitting, by the UE, the first UL transmission in thetransmission resource omitting a first TO of the K TOs that comprisesthe first OFDM symbol.

Optionally, in any of the preceding aspects, the first TO is omittedupon determining that the first TO has less than a threshold number ofOFDM symbols that are available for UL transmissions.

Optionally, in any of the preceding aspects, the first TO is omittedupon determining that the first TO is not configured for the initialtransmission.

Optionally, in any of the preceding aspects, the first TO is omittedupon determining that the first TO is not associated with a specificredundant version (RV) index.

Optionally, in any of the preceding aspects, transmitting the first ULtransmission in the transmission resource omitting the first TOcomprises transmitting, by the UE in a second TO that is subsequent tothe first TO comprising the first OFDM symbol, a first repetition of theK repetitions that is corresponding to the first TO.

Optionally, in any of the preceding aspects, the first TO and the secondTO are in different slots.

Optionally, in any of the preceding aspects, transmitting the first ULtransmission in the transmission resource omitting the first TOcomprises transmitting, by the UE, less than K repetitions in thetransmission resource during the time duration.

Optionally, in any of the preceding aspects, the method further includesre-mapping a redundant version (RV) sequence associated with the K TOsto the less than K repetitions, the RV sequence comprising a pluralityof RV indices.

Optionally, in any of the preceding aspects, transmitting the first ULtransmission in the transmission resource omitting the first TOcomprises transmitting, by the UE, the K repetitions during the timeduration, at least one repetition being transmitted in an OFDM symbolthat is subsequent to the K TOs.

Optionally, in any of the preceding aspects, transmitting the first ULtransmission in the transmission resource omitting the first OFDM symbolcomprises transmitting, by the UE, a repetition in OFDM symbols of afirst TO that comprises the first OFDM symbol, omitting the first OFDMsymbol.

Optionally, in any of the preceding aspects, the method further includespuncturing, by the UE, the repetition for transmitting the repetition inthe OFDM symbols of the first TO.

Optionally, in any of the preceding aspects, the method further includesperforming, by the UE, rate matching on the repetition for transmittingthe repetition in the OFDM symbols of the first TO.

Optionally, in any of the preceding aspects, transmitting the repetitionfurther comprises transmitting, by the UE, the repetition in a set ofOFDM symbols subsequent to the first OFDM symbol, the set of OFDMsymbols being available for UL transmissions.

Optionally, in any of the preceding aspects, the set of OFDM symbolscomprises consecutive OFDM symbols.

Optionally, in any of the preceding aspects, the K TOs are associatedwith a redundant version (RV) sequence comprising a plurality of RVindices, each TO being mapped to a RV index of the plurality of RVindices.

In accordance with another aspect of the present disclosure, a userequipment (UE) is provided, which includes a non-transitory memorystorage comprising instructions; and one or more processors incommunication with the memory storage. The one or more processorsexecute the instructions to determine that a transmission resourceincludes a first orthogonal frequency-division multiplexing (OFDM)symbol that is configured as a downlink symbol or as flexible, whereinthe transmission resource is allocated for uplink (UL) transmissionsduring a time duration, and comprises K transmission occasions (TOs), Kbeing an integer greater than 1; and transmit a first UL transmission inthe transmission resource omitting the first OFDM symbol. The first ULtransmission comprises K repetitions to be transmitted in the respectiveK TOs, and the K repetitions comprises an initial transmission and atleast one retransmission of the initial transmission.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured for downlink (DL) transmission.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured as flexible and dynamically configured asflexible.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured as flexible and dynamically configured for DLtransmission.

Optionally, in any of the preceding aspects, the first OFDM symbol issemi-statically configured by a higher-layer parameter comprising a timedivision duplex (TDD) UL-DL configuration common parameter or TDD UL-DLconfiguration dedicated parameter.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a communication system;

FIG. 2A illustrates a diagram of an embodiment electronic device (ED)such as a user equipment (UE);

FIG. 2B illustrates a diagram of an embodiment base station;

FIG. 2C illustrates a network for communicating data;

FIGS. 3A and 3B illustrate examples of a slot based grant-free resourceoccasion allocation to avoid conflict of resources;

FIG. 4 illustrates an example of a slot based grant-free resourceoccasion allocation at the OFDM symbol level to avoid conflict ofresources;

FIG. 5 illustrates another example of a slot based grant-free resourceoccasion allocation at the OFDM symbol level to avoid conflict ofresources;

FIG. 6 illustrates a further example of a slot based grant-free resourceoccasion allocation at the OFDM symbol level to avoid conflict ofresources;

FIG. 7 illustrates an example of a mini-slot based grant-free resourceoccasion allocation at the OFDM symbol level to avoid conflict ofresources;

FIGS. 8A, 8B and 8C illustrate examples of a mini-slot based grant-freeresource occasion allocation at the OFDM symbol level pertaining to slotboundaries;

FIG. 9 illustrates another example of a mini-slot based grant-freeresource occasion allocation at the OFDM symbol level to avoid conflictof resources;

FIG. 10 illustrates a further example of a mini-slot based grant-freeresource occasion allocation at the OFDM symbol level to avoid conflictof resources;

FIG. 11 illustrates yet another example of a mini-slot based grant-freeresource occasion allocation at the OFDM symbol level to avoid conflictof resources;

FIG. 12 illustrates a flowchart of an example grant-free transmissionscheme;

FIG. 13 illustrates a diagram of an example method for wirelesscommunications; and

FIG. 14 illustrates a diagram of a computing system according to anembodiment of the disclosure.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The structure, manufacture and use of the present embodiments arediscussed in detail below. It should be appreciated, however, that thepresent disclosure provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the disclosure, and do not limit the scope of the disclosure.

In this disclosure, grant-free transmissions refer to data transmissionsthat are performed without communicating grant-based signaling in adynamic control channel, such as a Physical Uplink Control Channel(PUCCH) or a Physical Downlink Control Channel (PDCCH). Grant-freetransmissions can include uplink (UL) or downlink (DL) transmissions,and should be interpreted as such unless otherwise specified. Grant-freeuplink transmissions are sometimes called “grant-less”, “schedule free”,or “schedule-less” transmissions. Grant-free uplink transmission canalso be referred to as “UL transmission without grant”, “UL transmissionwithout dynamic grant”, “transmission without dynamic scheduling”,“transmission using configured grant”. Sometimes, grant-free resourcesconfigured in RRC without DCI signaling may be called a radio resourcecontrol (RRC) configured grant (also referred to as Type 1). Grant-freeresource configured using both RRC and downlink control information(DCI) signaling may also be a configured grant, a DCI configured grantor another type of configured grant (sometime referred to as Type 2).

An UL transmission performed in grant-free resources configured inaccordance with Type 1 may be referred to as Type 1 grant-freetransmission. An UL transmission performed in grant-free resourcesconfigured in accordance with Type 2 may be referred to as Type 2grant-free transmission.

FIG. 1 illustrates an example communication system 100 in whichembodiments of the present disclosure could be implemented. In general,the system 100 enables multiple wireless or wired user devices totransmit and receive data and other content. The purpose of thecommunication system 100 may be to provide content (voice, data, video,text) via broadcast, narrowcast, user device to user device, etc. Thecommunication system 100 may operate by sharing resources such asbandwidth.

In this example, the communication system 100 includes electronicdevices (EDs) 110 a-110 c, radio access networks (RANs) 120 a-120 b, acore network 130, a public switched telephone network (PSTN) 140, theInternet 150, and other networks 160. Although certain numbers of thesecomponents or elements are shown in FIG. 1, any reasonable number ofthese components or elements may be included in the system 100.

The EDs 110 a-110 c are configured to operate, communicate, or both, inthe system 100. For example, the EDs 110 a-110 c are configured totransmit, receive, or both, via wireless or wired communicationchannels. Each ED 110 a-110 c represents any suitable end user deviceand may include such devices (or may be referred to) as a userequipment/device (UE), wireless transmit/receive unit (WTRU), mobilestation, fixed or mobile subscriber unit, cellular telephone, station(STA), machine type communication (MTC) device, personal digitalassistant (PDA), smartphone, laptop, computer, touchpad, wirelesssensor, or consumer electronics device.

In FIG. 1, the RANs 120 a-120 b include base stations 170 a-170 b,respectively. Each base station 170 a-170 b is configured to wirelesslyinterface with one or more of the EDs 110 a-110 c to enable access toany other base station 170 a-170 b, the core network 130, the PSTN 140,the Internet 150, and/or the other networks 160. For example, the basestations 170 a-170 b may include (or be) one or more of severalwell-known devices, such as a base transceiver station (BTS), a Node-B(NodeB), an evolved NodeB (eNodeB), a Home NodeB, a gNodeB, atransmission point (TP), a site controller, an access point (AP), or awireless router. Any ED 110 a-110 c may be alternatively or additionallyconfigured to interface, access, or communicate with any other basestation 170 a-170 b, the internet 150, the core network 130, the PSTN140, the other networks 160 or any combination of the preceding. Thecommunication system 100 may include RANs, such as RAN 120 b, whereinthe corresponding base station 170 b accesses the core network 130 viathe internet 150, as shown.

The EDs 110 a-110 c and base stations 170 a-170 b are examples ofcommunication equipment that can be configured to implement some or allof the functionality and/or embodiments described herein. In theembodiment shown in FIG. 1, the base station 170 a forms part of the RAN120 a, which may include other base stations, base station controller(s)(BSC), radio network controller(s) (RNC), relay nodes, elements, and/ordevices. Also, the base station 170 b forms part of the RAN 120 b, whichmay include other base stations, elements, and/or devices. Each basestation 170 a-170 b transmits and/or receives wireless signals within aparticular geographic region or area, sometimes referred to as a “cell”or “coverage area”. A cell may be further divided into cell sectors, anda base station 170 a-170 b may, for example, employ multipletransceivers to provide service to multiple sectors. In some embodimentsthere may be established pico or femto cells where the radio accesstechnology supports such. In some embodiments, multiple transceiverscould be used for each cell, for example using multiple-inputmultiple-output (MIMO) technology. The number of RAN 120 a-120 b shownis exemplary only. Any number of RAN may be contemplated when devisingthe communication system 100.

The base stations 170 a-170 b communicate with one or more of the EDs110 a-110 c over one or more air interfaces 190 using wirelesscommunication links. e.g., radio frequency (RF), microwave, infrared(IR), etc. The air interfaces 190 may utilize any suitable radio accesstechnology. For example, the communication system 100 may implement oneor more channel access methods, such as code division multiple access(CDMA), time division multiple access (TDMA), frequency divisionmultiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA(SC-FDMA) in the air interfaces 190.

A base station 170 a-170 b may implement Universal MobileTelecommunication System (UMTS) Terrestrial Radio Access (UTRA) toestablish an air interface 190 using wideband CDMA (WCDMA). In doing so,the base station 170 a-170 b may implement protocols such as HSPA, HSPA+optionally including HSDPA, HSUPA or both. Alternatively, a base station170 a-170 b may establish an air interface 190 with Evolved UTMSTerrestrial Radio Access (E-UTRA) using LTE, LTE-A, and/or LTE-B. It iscontemplated that the communication system 100 may use multiple channelaccess functionality, including such schemes as described above. Otherradio technologies for implementing air interfaces include IEEE 802.11,802.15, 802.16, CDMA2000, CDMA2000 1×, CDMA2000 EV-DO, IS-2000, IS-95,IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemesand wireless protocols may be utilized.

The RANs 120 a-120 b are in communication with the core network 130 toprovide the EDs 110 a-110 c with voice, data and other services. TheRANs 120 a-120 b and/or the core network 130 may be in direct orindirect communication with one or more other RANs (not shown), whichmay or may not be directly served by core network 130, and may or maynot employ the same radio access technology as RAN 120 a, RAN 120 b orboth. The core network 130 may also serve as a gateway access between(i) the RANs 120 a-120 b or EDs 110 a-110 c or both, and (ii) othernetworks (such as the PSTN 140, the internet 150, and the other networks160). In addition, some or all of the EDs 110 a-110 c may includefunctionality for communicating with different wireless networks overdifferent wireless links using different wireless technologies and/orprotocols. Instead of wireless communication (or in addition thereto),the EDs 110 a-110 c may communicate via wired communication channels toa service provider or switch (not shown), and to the internet 150. PSTN140 may include circuit switched telephone networks for providing plainold telephone service (POTS). Internet 150 may include a network ofcomputers or subnets (intranets) or both, and incorporate protocols,such as IP, TCP, or UDP. EDs 110 a-110 c may be multimode devicescapable of operation according to multiple radio access technologies,and incorporate multiple transceivers necessary to support such.

Although FIG. 1 illustrates one example of a communication system,various changes may be made to FIG. 1. For example, the communicationsystem 100 could include any number of EDs, base stations, networks, orother components in any suitable configuration.

FIGS. 2A and 2B illustrate example devices that may implement themethods and teachings according to this disclosure. In particular, FIG.2A illustrates an example ED no corresponding to 110 a, 110 b, 110 c,and FIG. 2B illustrates an example base station 170 corresponding to 170a or 170 b. These components could be used in the system 100 or in anyother suitable system.

As shown in FIG. 2A, the ED 110 includes at least one processing unit200. The processing unit 200 implements various processing operations ofthe ED 110. For example, the processing unit 200 could perform signalcoding, data processing, power control, input/output processing, or anyother functionality enabling the ED 110 to operate in the communicationsystem 100. The processing unit 200 also supports the methods andteachings described in more detail above and below. Each processing unit200 includes any suitable processing or computing device configured toperform one or more operations. Each processing unit 200 could, forexample, include a microprocessor, microcontroller, digital signalprocessor, field programmable gate array, or application specificintegrated circuit.

The ED 110 also includes at least one transceiver 202. The transceiver202 is configured to modulate data or other content for transmission byat least one antenna 204 or NIC (Network Interface Controller). Thetransceiver 202 is also configured to demodulate data or other contentreceived by the at least one antenna 204. Each transceiver 202 includesany suitable structure for generating signals for wireless or wiredtransmission and/or processing signals received wirelessly or by wire.Each antenna 204 includes any suitable structure for transmitting and/orreceiving wireless or wired signals. One or multiple transceivers 202could be used in the ED 110 One or multiple antennas 204 could be usedin the ED 110. Although shown as a single functional unit, a transceiver202 could also be implemented using at least one transmitter and atleast one separate receiver.

The ED 110 further includes one or more input/output devices 206 orinterfaces (such as a wired interface to the internet 150). Theinput/output devices 206 facilitate interaction with a user or otherdevices (network communications) in the network. Each input/outputdevice 206 includes any suitable structure for providing information toor receiving information from a user, such as a speaker, microphone,keypad, keyboard, display, or touch screen, including network interfacecommunications.

In addition, the ED 110 includes at least one memory 208. The memory 208stores instructions and data used, generated, or collected by the ED110. For example, the memory 208 could store software instructions ormodules configured to implement some or all of the functionality and/orembodiments described above and that are executed by the processingunit(s) 200. Each memory 208 includes any suitable volatile and/ornon-volatile storage and retrieval device(s). Any suitable type ofmemory may be used, such as random access memory (RAM), read only memory(ROM), hard disk, optical disc, subscriber identity module (SIM) card,memory stick, secure digital (SD) memory card, and the like.

As shown in FIG. 2B, the base station 170 includes at least oneprocessing unit 250, at least one transmitter 252, at least one receiver254, one or more antennas 256, at least one memory 258, and one or moreinput/output devices or interfaces 266. A transceiver, not shown, may beused instead of the transmitter 252 and receiver 254. A scheduler mayalso be coupled to the processing unit 250. The scheduler may beincluded within or operated separately from the base station 170. Theprocessing unit 250 implements various processing operations of the basestation 170, such as signal coding, data processing, power control,input/output processing, or any other functionality. The processing unit250 can also be configured to implement some or all of the functionalityand/or embodiments described in more detail above. Each processing unit250 includes any suitable processing or computing device configured toperform one or more operations. Each processing unit 250 could, forexample, include a microprocessor, microcontroller, digital signalprocessor, field programmable gate array, or application specificintegrated circuit.

Each transmitter 252 includes any suitable structure for generatingsignals for wireless or wired transmission to one or more EDs or otherdevices. Each receiver 254 includes any suitable structure forprocessing signals received wirelessly or by wire from one or more EDsor other devices. Although shown as separate transmitter 252 andreceiver 254, these two devices could be combined as a transceiver. Eachantenna 256 includes any suitable structure for transmitting and/orreceiving wireless or wired signals. While a common antenna 256 is shownhere as being coupled to the transmitter 252, one or more antennas 256could be coupled to the receiver 254, allowing separate antennas 256 tobe coupled to the transmitter and the receiver as separate components.Each memory 258 includes any suitable volatile and/or non-volatilestorage and retrieval device(s) such as those described above inconnection to the ED 110. The memory 258 stores instructions and dataused, generated, or collected by the base station 170. For example, thememory 258 could store software instructions or modules configured toimplement some or all of the functionality and/or embodiments describedabove and that are executed by the processing unit(s) 250.

Each input/output device 266 permits interaction with a user or otherdevices (network communications) in the network. Each input/outputdevice 266 includes any suitable structure for providing information toor receiving/providing information from a user, including networkinterface communications.

Grant-Free Transmissions

The base stations 170 are configured to support wireless communicationwith EDs 110, which may each send grant-free uplink transmissions.Uplink transmissions from the EDs 110 are performed on a set oftime-frequency resources. A grant-free uplink transmission is an uplinktransmission that is sent using uplink resources without the basestations 170 dynamically allocating resources to request/grantmechanisms. By performing grant-free transmissions, total networkoverhead resources may be saved. Furthermore, time savings may beprovided by bypassing the request/grant procedure. An ED sending agrant-free uplink transmission, or configured to send a grant-freeuplink transmission, may be referred to as operating in grant-free mode.Grant-free uplink transmissions are sometimes called “grant-less”,“schedule free”, or “schedule-less” transmissions. Grant-free uplinktransmissions from different EDs may be transmitted using shareddesignated resource units, in which case the grant-free uplinktransmissions are contention-based transmissions. One or more basestations 170 may perform blind detection of the grant-free uplinktransmissions.

In a wireless network according to an embodiment, any ED can beconfigured for grant-based or grant-free transmissions depending on,e.g., the application and device types and requirements. Usually, agrant-free transmission may require resource (pre-) configuration at theED connection setup and have resource reconfiguration or an updateduring operation. In some embodiments, the grant-free resources can beconfigured for EDs by broadcast or multi-cast signaling in somescenarios. Two or more grant-free transmissions can share the sameconfigured resources. Furthermore, a grant-based transmission can usededicated resources or can share resources (fully or partially) withgrant-free resources in a time interval.

Any of the grant-free and grant-based transmissions can be used for anyapplication traffic or services type, depending on the associatedapplication requirements and quality of service (QoS). By way of anon-limiting example, grant-free transmission can be used for:ultra-reliable low latency communication (URLLC) traffic to satisfy thelow latency requirement; enhanced mobile broadband (eMBB) traffic withshort packets to save signaling overhead; URLLC traffic having lowlatency requirements; and eMBB traffic to dynamically take advantage oflink adaptation and enhance resource utilization and spectrumefficiency.

One ED or a group of EDs may have a group ID or a Radio NetworkTemporary ID (RNTI; e.g., grant-free (GF)-RNTI or grant-based (GB) RNTI)to share the same parameter or resource configuration. The group ID canbe pre-configured, or dynamically configured to each ED. The parameteror resource configuration to the ED(s) with the group ID can be done bysemi-static or dynamic signaling. In some embodiments, the group ID canbe used for, e.g., resource deactivation or activation for the EDs inthe group. By way of a non-limiting example, the resources beingactivated or deactivated can include frequency, time, and a referencesignal (RS) associated with each ED in the group.

Grant-Free Resource Structure

To support grant-free transmissions, the associated resources configuredfor an ED or a group of EDs can include any or all of the following:

1) Frequency resources in a transmission time interval (TTI), e.g. asymbol, mini-slot or slot. In one example, a physical resource block(PRB) scheme is provided. The PRB scheme indicates a physical startingfrequency resource block (RB) and a size of the RB.

2) Time resources, including starting/ending position of one datatransmission time interval. For example, a TTI can be one symbol,mini-slot, or slot.

3) Reference signal (RS) configurations, where each ED can be configuredwith one or more reference signals (RSs), e.g. demodulation referencesignals (DMRSs) depending on scenarios involved. For a group of EDs,each ED may or may not have a different RS or have a different set ofRSs. Note that different RSs can be orthogonal or non-orthogonal to eachother depending on an application, e.g., such as a URLLC application ora massive machine-type communication (mMTC) application.

4) ED/ED group specific hopping parameters, which may include one of thefollowing two parameters. One parameter may include a hopping patterncycle period. In one embodiment, an absolute reference duration (e.g.,20 TTIs before repeating itself) is defined. During the absolutereference duration, the number of hopping steps (e.g., 10 times) to takebefore repeating the hopping pattern again can be determined based onperiodicity of time interval resource accessible for grant-freetransmissions (e.g., 2 TTIs). In another embodiment, an absolute numberof hopping times can be defined, for example hopping 20 times beforerepeating itself. Other parameter(s) may include a hopping pattern indexor indices, where one ED may have one or more hopping pattern indices.

5) One or more hybrid automatic repeat request (HARQ) process IDs perED.

6) One or more modulation and coding schemes (MCSs) per ED, where agrant-free ED can indicate explicitly or implicitly which MCS to use fora transmission

7) Number of grant-free transmission repetitions K, one or more K valuescan be configured for an ED, where which K value to use depends oncertain rule taking into account ED channel conditions, service types,etc.

8) Power control parameters, including power ramping step size (e.g.,for an ED).

9) Other parameters, including information associated with generalgrant-based data and control transmissions. Note that sometimes, asubset of grant-free resources can be referred to as “fixed” or“reserved” resources; whereas a subset of grant-based resources can bereferred to as “flexible” resources, which can be dynamically scheduledby a base station.

Hybrid Automatic Repeat Requests

As discussed above, the ED 110 may be configured to use a particular setof resources for grant-free transmission. A collision may occur when twoor more of the EDs 110 attempt to transmit data on a same set of uplinkresources. To mitigate possible collisions, the EDs 110 may useretransmissions. A retransmission, without grant, of an originalgrant-free uplink transmission is referred to herein as a “grant-freeretransmission”. Any discussion of a grant-free retransmission hereinshould be understood to refer to either a first or a subsequentretransmission. Herein, the term “retransmission” includes both simplerepetitions of the transmitted data, as well as retransmissions using anasynchronous hybrid automatic repeat request (HARQ), that is, acombination of high-rate forward error-correcting coding and physicallayer automatic repeat request (ARQ) error control.

In an embodiment, a number of automatic grant-free retransmissions maybe pre-configured, to improve reliability and eliminate latencyassociated with waiting for an acknowledgement (ACK) or a negativeacknowledgement (NACK) message. The retransmissions may be performed bythe ED 110 until at least one of the following conditions is met:

1) An ACK message is received from the base station 170 indicating thatthe base station 170 has successfully received and decoded a transportblock (TB). The ACK may be sent in a dedicated downlink acknowledgementchannel, sent as individual DCI, sent in a data channel, sent as part ofa group ACK/NACK, etc.

2) The number of repetitions reaches K. In other words, if the ED 110has performed K retransmissions and an ACK is still not received fromthe base station 170, then the ED 110 gives up trying to send the datato the base station 170. In some embodiments, K is semi-staticallyconfigured by the base station 170, such that the base station 170 orthe network can adjust K over time.

3) A grant is received from the base station 170 performing a grant-freeto grant-based switch.

In an embodiment, the grant-free retransmission may be triggered byreceiving a negative acknowledgment (NACK) message, or failing toreceive an acknowledgment (ACK) message. In an alternative embodiment, Kgrant-free retransmissions are performed irrespective of the responsefrom the base station 170.

The resources over which the one or more grant-free retransmissions areperformed may be pre-configured, in which case the base stationdetermines the resources based on a priori information. Alternatively,the resources over which the grant-free initial transmission or one ormore retransmissions are performed may be determined e.g. according toan identifier in a pilot signal of the original grant-free uplinktransmission. This may allow the base station to predict, or otherwiseidentify, which uplink resources will carry the one or moreretransmissions upon detecting the identifier in the pilot symbol.

Grant-free transmission reduces latency and control overhead associatedwith grant-based procedures, and can allow for moreretransmissions/repetitions to increase reliability. However, due to thelack of uplink scheduling and grant signaling, grant-free EDs may haveto be pre-configured to use a fixed modulation and coding scheme (MCS)level at least for initial grant-free transmission. In one embodiment,grant-free EDs are configured to use the most reliable MCS level for agiven resource unit for grant-free uplink transmissions.

FIG. 2C illustrates an example network 280 for communicating data. Thenetwork 280 comprises a Base Station (BS) 283 having a coverage area281, a plurality of mobile devices 282 (282 a, 282 b), and a backhaulnetwork 284. As shown, the base station 283 establishes uplink (longdashed line) and/or downlink (short dashed line) connections with themobile devices 282, which serve to carry data from the mobile devices282 to the BS 283 and vice-versa. Data carried over the uplink/downlinkconnections may include data communicated between the mobile devices282, as well as data communicated to/from a remote-end (not shown) byway of the backhaul network 284.

The network 280 may implement a grant-free uplink transmission.Grant-free uplink transmissions from different mobile devices may betransmitted using the same designated resources in which case thegrant-free uplink transmissions may support contention-basedtransmissions. One or more base stations, e.g. BS 283, may perform blinddetection on the grant-free uplink transmissions.

Grant-free uplink transmissions may be suitable for transmitting burstytraffic with short packets from the mobile devices 282 to the BS 283,and/or for transmitting data to the BS 283 in real-time or withlow-latency. Examples of applications in which a grant-free uplinktransmission scheme may be utilized include: massive machine typecommunication (m-MTC), ultra-reliable low latency communications(URLLC), smart electric meters, tele-protection in smart grids, andautonomous driving. However, grant-free uplink transmission schemes arenot limited to the applications described above.

The BS 283 may implement a grant-free uplink transmission scheme, anddesignated grant-free regions may be defined so that the mobile devices282 may contend for and access uplink resources without a request/grantmechanism. The grant-free uplink transmission scheme may be defined bythe BS, or it may be set in a wireless standard (e.g., 3GPP). Mobiledevices 282 may be mapped to various designated grant-free regions toavoid collision (i.e., when two or more mobile devices attempt totransmit data on the same uplink resource). However, if collisionoccurs, the mobile devices 282 may resolve collisions using anasynchronous HARQ (hybrid automatic repeat request) method. The BS 283may blindly (i.e., without explicit signaling) detect active mobiledevices and decodes received uplink transmissions.

Under this scheme, the mobile devices 282 may send uplink transmissionswithout the BS 283 allocating resources according to request/grantmechanisms. Therefore, total network overhead resources may be saved.Furthermore, this system may allow for time savings during uplink bybypassing the request/grant scheme. Although only one BS 283 and twomobile devices 282 are illustrated in FIG. 2C, a typical network mayinclude multiple BSs each covering transmissions from a varyingmultitude of mobile devices in its geographic coverage area.

The network 280 uses various high level signaling mechanisms to enableand configure grant-free transmissions. The mobile devices 282 capableof grant-free transmissions may signal this capability to the BS 283.This may allow the BS 283 to support both grant-free transmissions andtraditional signal/grant transmissions (e.g., for older mobile devicemodels) simultaneously. The relevant mobile devices may signal thiscapability by, for example, RRC (radio resource control) signalingdefined in the 3GPP (third generation partnership project) standard. Anew field may be added to the mobile device capability list in RRCsignaling to indicate whether the mobile device supports grant-freetransmissions. Alternatively, one or more existing fields may bemodified or inferred from in order to indicate grant-free support.

The BS 283 may also use high-level mechanisms (e.g., a broadcast channelor a slow signaling channel) to notify the mobile devices 282 ofinformation necessary to enable and configure a grant-free transmissionscheme. For example, the BS 283 may signal that it supports grant-freetransmissions, a search space location (defining a time-frequencyresource) and access codes for designated grant-free access regions, amaximum size of a signature set (i.e., the total number of signaturesdefined), a modulation and coding scheme (MCS) setting, and the like.Furthermore, the BS 283 may update this information from time to timeusing, for example, a slow signaling channel (e.g., a signaling channelthat only occurs in the order of hundreds of milliseconds instead ofoccurring in every transmit time interval (TTI)).

A network or a BS may update the amount of grant-free resourcesaccording to traffic load, number of UEs, RS resources, and/or physicalresources. The grant-free resources may include several predefinedpatterns, and each pattern may represent a certain amount of grant-freeresources assigned among all the resource with fixed pattern(s). In anembodiment, the grant-free resource configuration and update may onlyindicate an index of the pattern used. The BS may notify UEs of theupdate of grant-free resource assignment through system information, abroadcast channel, and/or a common control channel.

When grant-free resources increase or decrease, the sequence may bepunctured to maintain the controlled collision UE grouping and collisionfree RS assignment without signaling to individual UEs. After reducingthe grant-free resources to half, the number of opportunities may bereduced in half, but the number of max collisions and RS resourcerequirements may remain the same.

Semi-Static and Dynamic UL-DL Transmission Direction Configuration

The New Radio (NR) telecommunication protocol is expected to supportboth dynamic and semi-static UL-DL transmission direction configurationindication. The direction indication is for configuration oftransmission resources in a UL or DL direction. Semi-static is definedin comparison with the dynamic option that is operating in every timeslot. For example, semi-static can mean periodically within a given timeperiod, such as, for example, 200 or longer time slots. Semi-static canalso means configuring it once and only update once in a while.Sometimes semi-static configuration refers to a case where the signalingof the configuration is not in a dynamic signaling, e.g., the signalingcan be in broadcast signaling, RRC signaling, higher layer signaling, ora non-DCI signaling. Communications between the network and UEs may bebased on slots. Such slots are based on time division duplexing (TDD),with uplink transmissions occurring at times that are distinct fromdownlink transmission. In a specific example, each slot has 14 OFDMsymbols. A slot may include one or a combination of: downlink (DL)symbols; uplink (UL) symbols; guard symbols; and flexible, unknown orreserved symbols.

Alternatively, a slot may include one or a combination of DL symbols, ULsymbols, and other symbols that are neither DL nor UL symbols for aparticular UE, i.e., 110 transmission to and from the UE takes place onthose symbols. The other symbols may be called “flexible” or “unknown”in general from a perspective of UEs that are receiving the information.One or more of the indicated “flexible” or “Unknown” symbols may servethe purpose of guard period or gap between DL and UL symbol(s), i.e.,there may not be any “guard” symbol(s) identified in a slot, instead,some symbols can be called “flexible” or “unknown” generally, one ormore of which can be used as gap or can be overridden as DL or ULsymbols by other dynamic signaling. To this end, a slot may include oneor a combination of: downlink (DL) symbols; uplink (UL) symbols; andflexible or unknown symbols.

A user equipment (UE) can be semi-statically configured by higher layersignaling, such as a system information block (SIB) or radio resourcecontrol (RRC) signaling that indicates the allocation of UL and DLsymbols for different slots. Examples of such a higher layer signalingmay include TDD UL-DL configuration, UL-DL-configuration-common (alsoknown as TDD UL-DL configuration common) andUL-DL-configuration-dedicated (also known as TDD UL-DL configurationdedicated). This type of semi-static configuration can be periodic. Asemi-static UL-DL transmission direction configuration provides a slotformat per slot over a number of slots. The configuration may berepeated over different periods. The UE considers symbols in a slotindicated as downlink by the semi-static UL-DL transmission directionconfiguration (e.g. by a higher layer parameterUL-DL-configuration-common or by a higher layer parameterUL-DL-configuration-dedicated) as available for reception. The UEconsiders symbols in a slot indicated as uplink by a semi-static UL-DLtransmission direction configuration (i.e. a higher layer parameterUL-DL-configuration-common or by a higher layer parameterUL-DL-configuration-dedicated) as available for transmission. TheUL-DL-configuration-dedicated may only be able to override the flexiblesymbol indicated in UL-DL-configuration-common. In some embodiments, agrant-free enabled UE can detect dynamic slot format indication (SFI)and follow both dynamic and semi-static UL-DL configuration.

For example, a UE may be semi-statically configured using higher layersignaling including configurations such as a TDD UL-DL configuration,UL-DL-configuration-common (also known as TDD UL-DL configurationcommon) or UL-DL-configuration-dedicated (also known as TDD UL-DLconfiguration dedicated). The UL-DL-configuration-common is a commonconfiguration to multiple users, and the UL-DL-configuration-dedicatedis a UE specific configuration. The UE may be semi-statically configuredusing a higher layer signaling parameter, such as aUL-DL-configuration-common parameter, or a UL-DL-configuration-dedicatedparameter.

The semi-static UL-DL configuration may define each OFDM symbol of eachslot to be either “downlink” (DL), “flexible” (may subsequently beallocated for either DL or UL), or “uplink” (UL). Defining each OFDMsymbol being either DL, flexible or UL symbol may be referred in thisdisclosure as slot format or slot format information. A slot formatindicates a combination of one or more of:

which symbols (i.e. location within the slot) are downlink symbols;

which symbols are uplink symbols;

which symbols are flexible or unknown or reserved symbols.

A DL symbol refers to a symbol that is used for DL transmission, while aUL symbol refers to a symbol that is used for UL transmission. A symbolthat is configured as DL in a semi-static UL-DL configuration cannot beused for UL GF transmissions, and therefore it may be consider as aconflict if the same symbol is also configured for UL GF transmission.In some embodiments, a flexible symbol can be used for UL GFtransmission, i.e., the configured UL GF transmission on the symboloverrides the transmission direction of the symbol from “flexible” to“UL”, and it is not considered as a conflict. In some embodiments, theflexible symbol cannot be used for UL GF transmission without beingoverridden by dynamic SFI to UL transmission.

In order to facilitate dynamically changing the slot format, i.e.dynamically adjusting how the slot is subdivided as between uplink anddownlink transmissions, a slot format indication (SFI) can betransmitted from a network to a group of UEs. A UE may be furtherindicated for UL-DL configuration of a slot by a dynamic SFI. A dynamicSFI is typically indicated using a group common Physical DownlinkControl Channel (GC-PDCCH). A dynamic SFI can indicate the UL-DLconfiguration of a slot format for a slot or a group of slots. A UE maybe configured whether to monitor a dynamic SFI and/or how often tomonitor the dynamic SFI (e.g. the UE may be configured with a SFImonitoring periodicity). A dynamic SFI may override the transmissiondirection of a flexible symbol that is configured in semi-static UL-DLconfiguration. If a SFI is received that overrides a flexible symbol toa DL symbol or a flexible/unknown symbol, the overridden symbol may notbe available for UL grant-free transmission, i.e., if a grant-freetransmission is configured on that symbol, it cannot be transmitted onthat symbol.

The UL/DL transmission direction configuration may also be configured tomonitor a combination of semi-static UL-DL configuration and dynamicconfiguration using a slot format indication (SFI). In some embodiments,an SFI may be transmitted on a group common Physical Downlink ControlChannel (GC-PDCCH). The SFI may indicate the slot format information foran OFDM symbol, slot, or group of slots. For example, an OFDM symbol ina slot may be allocated for “downlink” (DL), “flexible” (maysubsequently be allocated for either DL or UL), or “uplink” (UL).

Grant-Free Reosurce Configuration

NR is also expected to support UL transmission resource allocation onthe basis of a slot, where a slot includes a plurality of orthogonalfrequency divisional multiplexed (OFDM) symbols, and a mini-slot, wherea mini-slot is a set of OFDM symbols that is less than the size of aslot. For example, a slot may include 14 OFDM symbols. A mini-slotwithin the slot may be comprised of 2 OFDM symbols, 4 OFDM symbols or 7OFDM symbols. In NR, a downlink control indication (DCI) message may beused to define resource allocation on a slot, mini-slot, or symbolbasis.

A transmission occasion (TO) in the disclosure may refer to atransmission resource, which includes at least the resource in the timedomain. Specifically, a TO may include indication of a period of timeduring which transmission is performed. In some embodiments, the timedomain property of TO may be represented in terms of OFDM symbols orslots. For example, a TO may include one or more OFDM symbols. The termsof “transmission occasion”, and “transmission opportunity” may be usedinterchangeably in the present disclosure.

Allocation of grant-free transmission occasions may occur in a number ofdifferent ways. Some examples of grant-free allocation are described ina co-pending U.S. patent application Ser. No. 15/830,928. In someembodiments, the allocation may be made using a grant-free scheme inwhich only RRC messaging is used. In some embodiments, the allocationmay be made using a grant-free scheme in which RRC messaging is used incombination with downlink control information (DCI) messaging.Information or parameters that may be provided to configure thegrant-free allocation in either scheme includes a periodicity thatdefines a time duration between grant-free resource occasions, an offsetthat defines the starting time reference of a grant-free resource, atime domain resource allocation configuration that defines further thelocation of grant-free resources in the time domain, a frequency domainresource allocation configuration that defines the frequency location ofa grant-free resource, a number of repetitions K of a grant-freetransmission and a redundancy version (RV) sequence. The time domainresource allocation configuration may define the starting and endingsymbol of the first repetition resource of each transport block (TB).The frequency domain resource allocation configuration may includeBandwidth part (BWP) information and resource block assignment, andreference signal (RS) parameters. Other information may also beincluded, such as modulation and coding scheme (MCS) information.Allocation of the UL grant-free transmission occasions is expected to besupported on the basis of a slot or mini-slot.

With regard to UE specific information, the RRC signaling may be used tonotify UE capable of supporting a grant-free scheme about informationrelevant to grant-free transmission such as, but not limited to, a UEID, a DCI search space, grant-free transmission resources, RS resourcesand other relevant information that may include for example, MCS. TheRRC signaling may include a grant-free ID field (such as GF-RNTI) andone or more configuration fields for configuring for UL (gf-ConfigUL)and/or for configuring for downlink (DL) (gf-ConfigDL).

The signaling for grant-free resource allocation may include, but is notlimited to, information such as UL-TWG-periodicity, a time offset value,a time-domain-resource-configuration, a frequency domain resourceallocation configuration, a Demodulation Reference Signal (DMRS)configuration field UL-TWG-DMRS, a UL-TWG-MCS-TBS, a repetition K, andUL-TWG-RV-rep.

The UL-TWG-periodicity, denoted by P, is a periodicity that defines theinterval between two adjacent grant-free transmission resource bundles.Each grant-free resource bundle may include K transmission occasionsthat are allocated for K repetition of a transmission block (TB). The Krepetitions are considered to include a first transmission and K-1repetitions. The periodicity P may be defined as a number of symbols ora number of slots. The possible values of P can be different fordifferent numerologies, it may include 2 symbols, 7 symbols, 1 slot anda length equal to multiple slots.

A time offset value indicates the starting time location of onegrant-free resource, e.g. the offset value can indicate the startingtime location (e.g. a slot index) of the grant-free resource withrespect to a system frame number (SFN)=0. In some embodiments, theoffset may not need to be signaled, and it can have a default value,e.g. at slot 0.

Time-domain-resource-configuration (which may also be known asTime-domain PUSCH resources) provides additional parameters to indicatea time domain resource allocation configuration for grant-freetransmission opportunities. Time-domain-resource-configuration mayinclude the starting symbol and the length in terms of number of OFDMsymbols of the first repetition resource of each transport block (TB).In some embodiments, the time-domain-resource-configuration may indicatea row index of an RRC configured table (the table can be UE specific),where the row index defines a slot offset K2, and a start and lengthindicator SLIV, and the PUSCH mapping type to be applied in the PUSCHreception. For Type 1 grant-free transmission, the slot index K2 may beignored. The start and length indicator SLIV defines the starting symbolS relative to the start of the slot and the number of consecutivesymbols L counting from the symbol S. The mapping type may containmapping type A and B. For mapping type A, the location of a DMRS may befixed at a predefined symbol location within the slot (e.g. starting atthe 3^(rd) OFDM symbol of the slot). For mapping type B, the location ofthe DMRS among the slot may depends on the symbol location of thegrant-free PUSCH resources within the slot, for example, the DMRS maystart at the symbol S defined in SLIV. In some embodiments, the mappingtype can also be used to indicate whether the grant-free resourceallocation is the slot based repetition or mini-slot based repetition,e.g., mapping type A may indicate it is slot-based repetition whilemapping type B may indicate it is mini-slot based repetition. There mayalso be fields for grant-free specific power control related parameters,which may include target receive power P_0 and a path loss compensationfactor alpha.

The frequency domain resource allocation configuration defines afrequency location of a grant-free resource. It may include theBandwidth part (BWP) information and resource block assignment withinthe active BWP. The resource block assignment indicates which resourceblocks (RBs) or resource block groups (RBGs) are used for thetransmission. RBG is a set of consecutive physical resource blocksdefined by the RBG size as the number of RBs per RBG. The resource blockassignment may include the starting resource block (RB) or startingresource block group (RBG), and the number of RBs or RBGs for thefrequency resource of the grant-free transmission. Alternatively, theresource block assignment may include a bit map indicating which RBs orRBGs are used within a BWP.

In some embodiments, the frequency domain resource allocationconfiguration may work in a similar way as a frequency domain resourceallocation configuration works in a grant-based DCI case. An additionalsingle bit may be used in the frequency domain resource allocationconfiguration RRC parameter to indicate a frequency allocation type. Theadditional single bit can indicate one of two different types offrequency allocations. In an example of a first type (Type 0) offrequency resource allocation, resource block assignment informationincludes a bitmap indicating the RBGs that are allocated to thescheduled UE. The size and location of each RBG may be determined by thesize of the carrier bandwidth part and some RRC configured parametersrelated to RBG sizes. An example of a second type (Type 1) of frequencyresource allocation includes resource block assignment informationindicating, to a scheduled UE, a set of contiguously allocated localizedvirtual resource blocks within the active carrier bandwidth part. Anuplink resource allocation field for the second type includes a resourceindication value (RIV) corresponding to a starting virtual resourceblock (RB_(start)) and a length in terms of contiguously allocatedphysical resource blocks L_(RBs). The frequency resource allocationscheme Type 0 is supported for OFDM-based uplink data transmission(PUSCH). The uplink frequency resource allocation scheme Type 1 issupported for uplink data transmission (PUSCH) for both cases whentransform precoding is enabled or disabled.

For Type 1 grant-free UL transmission which is based on RRC configuredgrant-free resources, in some embodiments, the frequency domain resourceallocation may include a one-bit element in the RRC parameter toindicate a frequency allocation type (Type 0 or 1, the different typesof allocation are described above, to differentiate between the twotypes). As a result, a frequencyDomainAllocation field in RRC signalingthat is configured for Type 1 grant-free transmission can appear as Type0 (a bit map indicating which RBGs are used for the transmission), whichindicates a Type 0 uplink frequency domain resource allocation forgrant-free transmission, or Type 1 (resource indication value (RIV)),which indicates a starting virtual resource block and a length in termsof contiguously allocated physical resource blocks.

That is, the frequencyDomainAllocation field may include a bit mapindicating a Type 0 frequency domain resource allocation, or a RIVindicating a Type 1 frequency domain resource allocation.

The Demodulation Reference Signal (DMRS) configuration field UL-TWG-DMRSdefines the DMRS parameters allocation. For example, an antenna portvalue may be provided by UL-TWG-DMRS. TWG refers to “transmissionwithout grant”, which may be also called “grant-free” or “configuredgrant”.

The UL-TWG-MCS-TBS provides a MCS or a transport block size (TBS) valuefor grant-free transmission.

The periodicity (UL-TWG-periodicity) can be defined in multipledifferent ways depending on how the grant-free resource occasions areallocated. In some implementations, the periodicity is defined by theperiod between the two K bundled grant-free resource occasionscorresponding to K repetitions of a TB together with an offset value,and a manner of defining a size of the grant-free resource occasion,such as a starting OFDM symbol and the number of symbols L that arebeing allocated in a slot.

That is, in some embodiments, the periodicity defines a period betweentwo grant-free resources, with each resource including K TOs fortransmitting K repetitions of a TB. Other parameters configured for thegrant resource configuration include an offset value, which indicateswhere the starting slot of the resource is within a periodicity, aparameter for defining a size of a TO, a parameter indicating a startingOFDM symbol in a TO, and a parameter indicating the number of symbols Lthat are configured in a TO of a slot.

The repetition K defines the number of repetitions for each grant-freetransmission of a TB.

UL-TWG-RV-rep defines a redundancy version (RV) pattern. A transmissioncan be retransmitted or repeated multiple times to ensure that areceiver receives and can decode the transmission. The receiver cancombine multiple transmissions to decode the transmission. Initialtransmissions and retransmissions may use different redundancy versions(RVs). When data is encoded in a grant-free message generator, theencoded bits may be partitioned into different sets (that possiblyoverlap with each other). Each set is a different RV. For example, someRVs may have more parity bits than other RVs. Each RV is identified byan RV index (e.g. RV 0, RV 1, RV 2, . . . , etc.). When an uplinktransmission is sent using a particular RV, then only the encoded bitscorresponding to that RV are transmitted. Different channel codes may beused to generate the encoded bits, e.g. turbo codes, low-densityparity-check (LDPC) codes, polar codes, etc. An error control coder inthe grant-free message generator in the UE may perform the channelcoding.

The RV pattern is a sequence of indices, where each index is mapped to arespective one of the K resource occasions being allocated. The RVsequence can be repeated based on the value of K. For example, for thenth transmission occasion among K repetitions, n=1, 2, . . . , K, it isassociated with (mod(n−1,4)+1)th value in the configured RV sequence.Examples of RV sequences include one of {0 0 0 0}, {0 2 31} or {0 3 03}. In the examples shown there are four indices. For values of K equalto 1 or 2, only the first one or two indices of the RV sequence may bemapped to the respective K=1 or 2 resource occasions. For a value of Kequal to 4, the entire set of four indices of the RV sequence may bemapped to the K=4 resource occasions. For a value of K equal to 8, theentire set of four indices of the RV sequence may be mapped to the firstfour resource occasions and then repeated for the second four resourceoccasions.

SFI signaling may result in a change to the transmission directionalityof OFDM symbols in a slot. For instance, an OFDM symbol in a slot mayhave been allocated as a flexible symbol in the semi-static UL-DLtransmission direction configuration. The UE may then receive a dynamicSFI signal, which may override the symbol to be an UL or DL or unknownsymbol. If some OFDM symbols were indicated as UL symbols in the SFI,those OFDM symbols may be able to be used for UL grant-freetransmissions.

In some embodiments, UL grant-free transmissions are only transmitted inan OFDM symbol indicated for UL by a semi-static UL/DL configuration, ora flexible OFDM symbol that is specifically configured by the SFI to bean UL OFDM symbol. In some embodiments, an UL grant-free transmissionmay also be able to be transmitted at the location of an OFDM symbolthat is indicated as flexible by a semi-static UL-DL configuration. Insome embodiments, an UL grant-free transmission may only be able to betransmitted at the location of an OFDM symbol that is indicated asflexible by a semi-static UL-DL configuration, if the UE is notconfigured to monitor a SFI that indicates the transmission direction ofthis symbol, or if the UE detects a SFI that overrides the transmissiondirection of this symbol to uplink.

In the following, it is considered that a UE obtains the transmissiondirection of OFDM symbols used for grant-free transmission through aUL-DL transmission direction configuration. The UL-DL transmissiondirection configuration includes the semi-static UL-DL transmissiondirection configuration and a dynamically configured SFI, if the UE isconfigured to monitoring the dynamic SFI and detects the dynamic SFI forthe transmission direction configuration of the resource. For notationalsimplicity, the UL-DL transmission direction configuration may bereferred to as a UL-DL configuration in this disclosure.

Aspects of the present application pertain to enabling the UE to updateUL grant-free transmission resources to resolve a conflict of thesemi-static or semi-persistently allocated grant-free transmissionresources with the UL-DL transmission direction configuration. Aspectsof the present application may also pertain to enabling the UE to updatethe allocation of UL grant-free transmission opportunities to avoidconflict with transmission resources allocated for control signals,reference signals or other data signals. Transmission resources used forcontrol signals may include OFDM symbols that have been configured forcontrol information such as scheduling requests (SR), HARQ feedback orother Physical Uplink Control Channel (PUCCH) signals. Transmissionresource reference signals may include the configuration of soundingreference signal (SRS).The control signal or reference signal may beconfigured semi-statically (e.g. in RRC messages) or dynamically (e.g.in DCI). Aspects of the present application may also pertain totransmitting the grant-free transmission on a new set of resources in acase where the allocated grant-free resource is in conflict with theUL-DL transmission direct configuration or a configuration of areference, control or data signal. Note that all the method/exampledescribed for the conflict resolution of UL grant-free resourceconfiguration with the UL-DL configuration can also be applied to theconflict resolution of UL grant-free resource configuration and theconfiguration of control signal, reference signals and other datasignals.

In LTE, for a frame having 10 ms subframes, where some of the subframesin the frame are used for DL and some of the subframes are used for UL.LTE semi-persistent scheduling (SPS) does not support dynamic timedivisional duplexing mechanism (i.e. indicating TDD UL-DL configurationdynamically). If the schedule interval or periodicity of an SPStransmission is greater than 10 ms, then the periodicity is rounded toan integer number of 10 ms subframes. This is because the supported TDDUL-DL configuration is defined based on a pattern of each sub frameamong one frame being an UL subframe, DL subframe or special subframe,and the same TDD UL-DL configuration is used for each frame which is 10ms in length. Therefore, if the first SPS resource is located on an ULsubframe, a next transmission opportunity also occurs in a UL subframe.If the periodicity is less than 10 ms, then the SPS transmission isdropped if the transmission is located in a DL subframe or a specialsubframe.

The resource configured for grant-free repetition can be slot basedrepetition or mini-slot based repetition. Slot based repetition meansthere is at most one repetition per slot, while mini-slot basedrepetition may support multiple grant-free repetitions per slot, whereeach grant-free transmission occasion may include a number of OFDMsymbols.

In some embodiments, a decision is to be made as to whether to use asingle transmission occasion per slot or multiple transmission occasionsper slot (mini-slot) approach. In some embodiments, a decision is madebased on periodicity P and a repetition number K. For example, if P/K<=1slot, where P is the periodicity and K is the number of repetitions perperiod, then in this scenario, a mini-slot based repetition can be usedIn some embodiments, a decision is made based on if P/K>1 slot. In thisscenario, a slot based repetition with 1 repetition per slot can beused. The offset is an integer number of slots and only useful if P>1slot. More generally, while 1 slot is used in the examples above as acomparative value for P/K, it should be understood that some otherthreshold could be used to make the determination other than a slot.

In one example, if P/K<=1 slot, where P is the periodicity and K is thenumber of repetitions per period, then, slot based repetition is used.In another example, if P/K<1 slot, where P is the periodicity and K isthe number of repetitions per period, then a mini-slot based repetitionmay be used; otherwise, if P/K>=1 slot, slot based repetition is used.

For a Type 1 grant-free transmission, the RRC configured periodicity P,the offset O, and time-domain-resource-allocation (also known astimedomainconfiguration), which defines a starting symbol S and a lengthof symbols L), the repetition K, the RV pattern, and UL-TWT-RV-reptogether define the transmission occasions (TOs) for K repetitions of aTB. When P>=1 slot, the starting transmission occasion of the Krepetitions of each TB is located in slot M=Offset+N*P (with all unitconverted to slot), where N is an integer and denotes a periodicityindex while P denotes the duration of the period. If P<1 slot, e.g., P=2or 7 symbols, the starting symbol of the first grant-free TO isdetermined by the starting symbol S and the length L fromtime-domain-resource-allocation at a slot determined by the offset (O).For a slot based repetition, the following K−1 grant-free TOs for therepetitions of the same TB are located in the subsequent K−1 slotsfollowing the first TO with the same starting symbol and length as thefirst TO. For a mini-slot based repetition, the following K−1 grant-freeTOs for the repetitions of the same TB are located in the followingsymbols with length L following the previous TO of the same TB.

For a Type 2 grant-free transmission, the periodicity P is defined inthe RRC. The offset is determined when slot activation DCI received. The“timedomainconfiguration” includes SLIV and a slot offset K2, where K2is the offset between the DCI and the transmission opportunity).

In situations where there is 110 conflict between a previously allocatedgrant-free resource allocation and a UL-DL configuration, then aresource occasion allocated for grant-free transmission is identifiedwithin a slot based on an offset from a reference point and the definedperiodicity allocated for the grant-free transmission. A resourceoccasion is then allocated for repetitions in subsequent slots. When aconflict arises between a previously allocated grant-free resourceoccasion and a UL-DL configuration, then the UE can take steps to modifythe grant-free allocation to mitigate the conflict.

An example of a conflict may include a scenario in which the number ofOFDM symbols available for UL traffic that can be allocated for agrant-free transmission occasion is less than or equal to α×L, where0≤α≤1 and α is a configurable, predefined ratio, and L is the length ofOFDM symbols configured to be used for the grant-free resource occasion.Another example of a conflict may include a scenario in which the numberof OFDM symbols available for UL traffic that can be allocated for agrant-free transmission occasion is less than L. In another word, thereis at least one OFDM symbol configured by UL-DL configuration that isnot available for UL transmission. Another example of a conflict mayinclude a scenario in which the number of OFDM symbols available for ULtraffic that can be allocated for a grant-free transmission occasion isless than or equal to a predefined or configured threshold. Anotherexample of a conflict may include a scenario in which the number of OFDMsymbols available for UL traffic that can be allocated for grant-freetransmission occasion is, for a slot based repetition, the number ofOFDM symbols available for UL traffic in a slot, and is less than orequal to L. Another example of a conflict may include a scenario inwhich the number of OFDM symbols available for UL traffic that can beallocated for grant-free transmission have at least some overlap with aconfigured reference signal, control signal or data signal.

As described above, an example conflict may include a scenario in whichthe number of OFDM symbols available for UL traffic that can beallocated for grant-free transmission occasion is, for a slot basedrepetition, the number of OFDM symbols available for UL traffic in aslot, and is less than or equal to L. This example of conflict is for aslot based repetition, and the number of OFDM symbols available for ULtraffic in the slot allocated for grant-free transmission occasion isless than or equal to L.

The OFDM symbols that can be considered to be available for ULgrant-free transmission occasions include at least one of 1) an ULsymbol configured by a semi-static UL/DL transmission directionconfiguration, 2) an UL symbol or flexible/unknown symbol configured bya semi-static UL-DL transmission direction configuration, 3) an ULsymbol or flexible/unknown symbol configured by a semi-static UL-DLtransmission direction configuration that is not overridden by a dynamicSFI, 4) a symbol that is configured not as a DL symbol by a semi-staticUL-DL transmission direction configuration, 5) a flexible symbol asconfigured by a semi-static UL-DL transmission direction configuration,but reconfigured to be an UL symbol by a dynamic SFI, 6) a flexiblesymbol as configured by a semi-static UL-DL transmission directionconfiguration, but reconfigured to be an unknown/flexible symbol by adynamic SFI, where for any of 1) to 6), the symbol does not conflictwith a configuration of other signals. The above confliction conditionand definition of available UL symbols according to the UL-DLconfiguration may be applicable to all examples/schemes described inthis disclosure. For notational simplicity, we may simply use conflictor in conflict to refer to any of the above conflict conditions, and wemay simply use available OFDM symbols or available UL OFDM symbols torefer to any of the definition of available symbols above based on theUL-DL configuration.

As one example, the OFDM symbols that can be considered to be availablefor UL grant-free transmission occasions include 1) an UL symbolconfigured by a semi-static UL/DL transmission direction configuration;2) a flexible symbol as configured by a semi-static UL-DL transmissiondirection configuration, but reconfigured to be an UL symbol by adynamic SFI. In this case, all the other configurations of OFDM symbolsconfigured by the UL-DL transmission direction configuration may beconsidered not available for UL transmission

In some embodiments, a grant-free allocation can be performed to avoidconflict between a previously allocated grant-free resource allocationand a UL-DL configuration for slot based repetition (i.e. on a singletransmission per slot basis). In this case, based on grant-free resourceconfiguration, a resource occasion is allocated for a first transmissionin a first slot, which is determined by the periodicity, offset andtime-domain-resource-allocation as described earlier, and resourceoccasions for the following K−1 repetitions of the TB are allocated insubsequent slots. FIGS. 3A, 3B, 4, 5 and 6 are examples pertaining to asingle grant-free resource occasion being allocated per slot.

FIG. 3A illustrates an example of a portion of a transmission resourceincluding io slots that are consecutive in the time domain and that canbe used for DL and/or UL traffic. It is indicated that slots 2 to 5 werepreviously allocated by RRC for UL grant-free transmission occasions.Slot 2, 3, 4, 5 are considered as the 1^(st), 2^(nd), 3^(rd), and 4^(th)previously allocated grant-free TOs. For example, the first TO in slot 2is determined by the periodicity and offset in RRC configurations. TheOFDM symbols within slot 2 are determined by the starting symbol S andlength L configured in time-domain-resource-allocation. The number ofrepetition K is configured to be 4. Therefore, in the case of noconflict, the same symbols in slot 3 to slot 5 are used for thefollowing K−1 transmission occasions. Based on a UL-DL configuration,which may be the result of a semi-static UL-DL configuration or theresult of a semi-static UL-DL configuration and a dynamic SFI, thesymbols within each slot may be indicated as DL, UL or flexible symbols.Slot 2 may have some conflict with the allocated grant-free resource forthe TO based on the UL-DL configuration. There are different definitionsof conflict conditions that may be applied here as described earlier inthis disclosure. For example, if the slot is a DL only or DL centricslot (majority of the symbols are indicated as DL symbols), or if thenumber (X) of available UL symbols in the slot is less than A, i.e., X<A(A is a predefined threshold, e.g. A=0,1), or if the number (X) ofavailable UL symbols in the slot is less than L, i.e., X<L , where L isthe length of the symbols configured for the TO. UL-DL configuration ofSlots 3 to 10 does not have any conflict with grant-free resourceallocations. For example, slots 3 to 10 may be UL only or UL centricslots, or the slots do not satisfy the conflict condition with thegrant-free TO allocation.

FIG. 3A and FIG. 3B show two different solutions with regard toresolving the conflict. The UE may drop/omit the grant-free TO inconflict from the K repetitions as described in FIG. 3A or postpone thegrant-free TO as described in FIG. 3B. When the UE drops/omits the TO,the UE does not add additional TO beyond the originally configured KTOs. For slot based repetition, UE may postpone the TO to the next slotsthat are not in conflict. In FIG. 3A, the first slot previouslyallocated for the first grant-free TO, slot 2, is omitted as a ULgrant-free transmission occasion for use by the UE and the UE uses thepreviously allocated grant-free transmission occasions of slots 3 to 5.Slot 3 can be used as a first transmission of a TB, and slots 4 and 5used for the subsequent repetition transmissions of the same TB.

In a particular example, even though K, the number of repetitionsconfigured by the network, is equal to 4, only a total of 3 repetitiontransmissions can be performed for the TB, which uses the 2^(nd), 3^(rd)and 4^(th) TO of the previously allocated grant-free transmissionoccasions as the updated grant-free transmission occasions for theactual grant-free transmission. In such an example, the indices in theRV sequence are mapped to the actual number of repetitions that isperformed. For an RV sequence={0 2 3 1} and K=4, when the firsttransmission occasion (slot 2) is dropped, the first three RV sequenceindices {0 2 3} are mapped to the three updated grant-free transmissionoccasions in slots 3 to 5. In this example, if the UE has UL grant-freetraffic that has arrived before slot 2, the UE can only perform 3repetitions of the TB at slot 3 to 5 using RV sequence {0 2 3},respectively.

In another example, when the transmission occasion is dropped, thecorresponding RV index is also dropped from the RV sequence/pattern. Insuch an example, the RV sequence is mapped to the previously allocatedgrant-free transmission occasions (in this example, the originalcontinuous slots, slot 2-5). For a RV sequence={0 2 3 1} and K=4, whenthe first transmission occasion (slot 2) is dropped, the remaining RVsequence indices {2 3 1} are mapped to slots 3 to 5, respectively.

FIG. 3B illustrates the method of postponing the grant-free transmissionoccasions in conflict, i.e., the UE delays the current transmissionoccasions and may add additional transmission occasions to try to keepthe number of grant-free transmission occasions to be K, the same as therepetition number original configured. The delay may be on a slot toslot basis for slot based repetition until a non-conflict TO is found.The UE may find the closest K non-conflict grant-free transmissionoccasions for the K repetitions within a window T after the firsttransmission occasion, where the length of the window T can be theperiodicity P configured for grant-free transmission. FIG. 3Billustrates a similar example group of 10 slots to be used for DL and/orUL traffic. It is indicated that slots 2 to 5 were previously allocatedfor grant-free transmission occasions. The first slot previouslyallocated for UL grant-free traffic, slot 2, is omitted as a ULgrant-free transmission occasion for use by the UE, and the UE thendetermines if there are K non-conflict transmission occasions availablewithin the period. The period can be the P symbols counting from thestarting symbol of the first transmission occasion, where P is theperiodicity of the grant-free resource configured in RRC. In FIG. 3B,the UE uses the previously allocated grant-free transmission occasionsof slots 3 to 5, but adds an additional transmission occasion, slot 6,so the overall number of transmission occasions is maintained at K=4. Itmay be considered that the K=4 transmission occasions are shifted to thenext available group of K=4 slots that is not conflict with the UL-DLconfiguration.

In some embodiments, if K non-conflict slots are not available within afirst period before a new transmission and associated repetitions arescheduled in a next period, then the UE may not allocate anytransmission occasions within the first period and wait for the nextperiod. In other embodiments, if K non-conflict slots are not availablewithin a first period before the start of the next period that isconfigured for a new transmission and associated repetitions, then theUE may not use any resources in the next period for grant-freetransmission occasions and therefore use less than K transmissionoccasions within the first period.

Note that although FIG. 3A and 3B are described based on a slot basis,i.e., the dropping, or postponing of a TO is slot by slot. The slot canbe generalized to any transmission unit, i.e., the slot shown in thefigures can be a transmission unit, for which the transmission unit canbe a slot, a mini-slot, an OFDM symbol, a subframe, a number of OFDMsymbols or any length of time unit for a grant-free transmission.

FIG. 4 illustrates an example of puncturing/rate matching solution forresolving the conflict. FIG. 4 shows how to determine the OFDM symbolsused for grant-free transmissions within the slot for slot-basedrepetition. The same principle may be applicable to the mini-slot basedrepetition. In FIG. 4, a more detailed view of a single slot having 14OFDM symbols is shown, where OFDM symbols 4 to 7 were previouslyallocated for grant-free transmission occasions by RRC signaling. Fromthe result of a UL-DL configuration of slot format, OFDM symbols 1 to 4are allocated for DL traffic, OFDM symbol 5 is allocated to be flexiblethat can be further configured for DL or UL traffic, and OFDM symbols 8to 14 are allocated for UL traffic. Since OFDM symbols 4 and 5 werepreviously allocated as part of a first grant-free transmissionoccasion, but is configured to be DL and flexible symbols by UL-DLconfigurations, respectively, this becomes a conflict condition for theUE with regard to the UL grant-free allocation.

FIG. 4 shows how only OFDM symbols 6 and 7 are used from the originalgrant-free transmission occasion of OFDM symbols 4 to 7 for the firstgrant-free transmission. As only two UL OFDM symbols based on UL-DLconfiguration are available to the UE, the UE punctures the informationof four OFDM symbols for transmission on the two available OFDM symbols,or rate matches the information for four OFDM symbols for transmissionon the two available OFDM symbols.

For the K transmission occasions allocated for the first transmissionand K−1 repetitions, each transmission occasion has a determined numberof available OFDM symbols, which may be based on the length L fromtime-domain-resource-configuration. In FIG. 4 for example, the firsttransmission occasion has only two available OFDM symbols. The second,third and fourth transmission occasions (not shown) for the second,third and fourth repetitions (the initial transmission is considered asthe first repetition), respectively, may each have four available OFDMsymbols. The K grant-free transmission occasions may each be configuredto utilize four OFDM symbols for transmission. A transport block size(TBS) is the number of information bits in each transport block. As withgrant-based transmission, TBS is also determined based on the configuredMCS value and the available time-frequency resources for thetransmission of the TB. The available time-frequency resources aretypically based on the available resource elements within the number ofOFDM symbols and the number of RBs in frequency domain allocated for thetransmission, excluding any reference signal or control signal allocatedin the resource. For the K grant-free transmission occasionscorresponding to the K repetition of a TB configured with a length of Lsymbols, assume the number of available UL symbols are X₁, X₂, . . . ,X_(K) for the 1^(st), 2^(nd), . . . , K-th GF transmission occasionsbased on the UL-DL configuration. In order to combine all therepetitions of the TB for better detection, the TBS of all the Krepetitions should be kept the same. A TBS for transmission ofinformation by the grant-free allocation is determined based on theconfigured MCS and time-frequency resources derived based on a number Yof OFDM symbols, where Y can be equal to (i) a number L of OFDM symbolsconfigured by the network, where L is the length configured intime-domain-resource configuration, (ii) a number of available UL OFDMsymbols in the first transmission occasion, or (iii) a minimum number ofavailable UL OFDM symbols from the set of available UL OFDM symbols foreach of the K transmission occasions of the same TB (.e., Y=min{X₁, X₂,. . . , X_(K)}. The UL grant-free information can be prepared fortransmission based on the available UL OFDM symbols to be used for eachgrant-free transmission occasion. The TBS is then rate matched to theavailable UL OFDM symbols X_(i) in i-th grant-free transmission occasionof the TB. For the i-th grant-free transmission occasion, if the Y isless than the available number of UL OFDM symbols for a given grant-freetransmission occasion X_(i) then the available OFDM symbols can befilled using a cyclic repetition of the Y OFDM symbols that is used todetermine the TBS. For example, if only two OFDM symbols are needed, butfour OFDM symbols are available, then the same two OFDM symbols can betransmitted twice over the four available OFDM symbols. If Y is morethan the available number of UL OFDM symbols for a given transmissionoccasion, then the available UL OFDM symbols can be filled with a set ofOFDM symbols that have been punctured, or otherwise rate matched. IfY=X_(i), then there may be no puncturing/rate matching or cyclicrepetition that needs to be done. When puncturing/rate matching isperformed, the location of DMRS symbols may also need to bepredetermined based on the X_(i) available UL OFDM symbols instead ofthe original L configured OFDM symbols, for example, the DMRS may belocated starting in the first symbol of the available X_(i) UL OFDMsymbols.

The following gives an example of determining the TBS. The configuredMCS information indicates a MCS index which provides the modulationscheme and the target code rate. If the number of configured OFDM symbolfor the GF TO is L, and the actual available UL OFDM symbol for the GFTO is X, where X<L, the UE may determine the TBS according to the Lsymbols. If the configured DMRS is located outside the X symbols, the UEshould assume the DMRS is located within the X symbols (e.g. starting atfirst symbol of the available L symbol). The UE calculate the availableresource elements (RE) for data transmission based on the time-frequencyresource of the X symbol along with the resource blocks assigned in thefrequency domain after removing the REs used for DMRS transmission. TheUE can then determine the number of coded bits that can fit in theavailable REs based on the modulation scheme. Then UE can determine theTBS based on the number of coded bits along with the target code rate.After determining the TBS, the UE can then select the mother code usedfor channel coding (e.g. based on LDPC codes or turbo codes). Afterthat, the desired encoded bits can be chosen based on the RV using ratematching and mapped to the available resources for transmission.

There are different ways of doing puncturing/rate matching. For example,if the TBS is based on the original configured L OFDM symbols and only XUL OFDM symbols are available for the TO, then after determining theTBS, one method to do puncturing is to do rate matching and mapping tothe resources exactly the same based on the L configured resources.However, the modulated symbols that are originally to be transmitted onthe OFDM symbols outside the X available UL symbols are not transmitted.This is one method of puncturing. Another way to do puncturing/ratematching is that, after determining the TBS, the UE first recalculatesthe code rate based on the available UL resources given by the Xavailable UL symbol. Because X<L, the new target rate should be muchsmaller than the target code rate indicated by the MCS configuration.The UE then reselect the mother code based on the new target code rateand re-do rate matching and remap encode bits to the available ULresources in the X available UL symbols. Note that the TBS determinationand puncturing/rate matching methods described above can apply to allthe examples/methods/schemes in this disclosure.

Note that in the few examples described in this disclosure, flexible isconsidered to be not available for UL grant-free transmission. However,in some embodiments, flexible can be considered as available for ULgrant-free transmission, i.e., it can be overridden by the UL grant-freeconfiguration to be used for UL grant-free transmission. In this case, aflexible symbol can be treated the same as an UL symbol for the purposeof determining whether there is conflict between the configuredgrant-free resources or transmission occasions and the UL-DLconfiguration and the respective UE behavior. In some embodiments, aflexible symbol in a semi-static UL-DL configuration can be consideredavailable for UL grant-free transmission. In some embodiments, aflexible symbol right after a DL symbol in a semi-static UL-DLconfiguration may be considered not available for UL grant-freetransmission, and any other flexible symbol in the semi-static UL-DLconfiguration may be considered available for UL GF transmission.However, if a dynamic SFI is received by the UE which overrides theflexible symbol to be a DL symbol or flexible/unknown symbol, the symbolmay be no longer available for UL grant-free transmission.

Another solution with regard to resolving a conflict involves the UEpostponing the grant-free transmission occasion. For a slot basedrepetition, UE may postpone the GF TO within the slot until Lconsecutive OFDM symbols are available. Then the postponed L OFDMsymbols may replace the originally configured L symbols as thegrant-free TO. An example is shown in FIG. 5. FIG. 5 illustrates anotherdetailed view of a single slot having 14 OFDM symbols. It is indicatedthat OFDM symbols 4 to 7 were previously allocated for a grant-freetransmission occasion by RRC signaling. From the results of UL-DLconfiguration, OFDM symbols 1 to 4 are allocated for DL traffic, OFDMsymbols 5 and 6 are allocated to be flexible, and OFDM symbols 7 to 14are allocated for UL traffic. Since OFDM symbols 4 to 6 were previouslyallocated as part of a first grant-free transmission occasion, but theyare configured in UL-DL configuration to be DL symbol and flexiblesymbol, this becomes a conflict condition for the UE with regard to theUL grant-free allocation.

FIG. 5 shows how the grant-free transmission occasion of four OFDMsymbols for a first transmission is shifted, or postponed, from theoriginal OFDM symbols 4 to 7 to the first set of four OFDM symbolsavailable for UL transmission, that is OFDM symbols 7 to 10. In someembodiments, if a flexible symbol is configured by a semi-static UL-DLconfiguration and it is not overridden by a SFI, the flexible symbol maybe considered to be available for UL grant-free transmission. In thiscase, in the example in FIG. 5, if symbols 5 and 6 are flexible symbolsindicated by the semi-static UL-DL configuration, the UE may shift tosymbol 5 to 8 for this grant-free transmission occasion. In anotherembodiment, if the flexible symbol is configured by the semi-staticUL-DL configuration and it is not overridden by a SFI, flexible symbolsthat are not immediately following a DL symbol may be considered to beavailable for UL grant-free transmission. In this case, in the exampleof FIG. 5, symbols 5 and 6 are flexible symbols indicated by thesemi-static UL-DL configuration, the UE may shift to symbols 6 to 9 forthis grant-free transmission occasion.

FIG. 6 illustrates another detailed view of a single slot having 14 OFDMsymbols. It is indicated that OFDM symbols 4 to 7 were previouslyallocated for grant-free transmission occasions by RRC signaling. Fromthe results of a UL-DL configuration of slot format, OFDM symbols 1 to10 are allocated for DL traffic, OFDM symbol 11 is allocated to beflexible and OFDM symbols 12 to 14 are allocated for UL traffic. Thisleaves only three OFDM symbols that could possibly be used for ULgrant-free transmission occasions in this slot. Since there are onlythree OFDM symbols available for an UL grant-free transmission occasion,which is less than the four OFDM symbols configured to be used for an ULgrant-free transmission occasion, this becomes a conflict condition forthe UE with regard to the UL grant-free allocation.

In the example of FIG. 6, with only three OFDM symbols available, the UEcan use the three OFDM symbols by puncturing the information for fourOFDM symbols on the three available OFDM symbols, or rate matching totransmit the information for four OFDM symbols on the three availableOFDM symbols.

In some embodiments, a grant-free allocation can be performed to avoidconflict between a previously allocated grant-free transmissionallocation and a UL-DL configuration for mini-slot based repetition,which supports more than one transmission repetitions per slot. In thiscase, a transmission occasion is allocated for a first transmission of aTB in a first slot, and transmission occasions for up to K−1 subsequentrepetitions of the TB are continued in the same slot and possibly into asubsequent slot.

While the examples described above with regard to FIGS. 3 to 6 pertainto one grant-free transmission occasion per slot, which can be referredto as “slot-based”, additional examples described below pertain to theuse of multiple grant-free transmission occasions being allocated perslot. Each transmission occasion can be a set of up to L OFDM symbolsthat are configured for the grant-free allocation. The set of OFDMsymbols may be considered a mini-slot. FIGS. 7, 8, 9, 10 and 11 areexamples pertaining to mini-slot based repetition, i.e., multiplegrant-free transmission occasions can be allocated per slot.

FIG. 7 illustrates a detailed view of a single slot having 14 OFDMsymbols. In FIG. 7, it is indicated that OFDM symbols 4 to 7 werepreviously allocated for grant-free transmission occasions by RRCsignaling. From the result of a UL-DL configuration of slot format, OFDMsymbols 1 to 4 are allocated for DL traffic, OFDM symbol 5 is allocatedto be flexible and OFDM symbols 6 to 14 are allocated for UL traffic.Since OFDM symbols 4 and 5 were previously allocated as UL grant-freetransmission occasions, but are configured in the UL-DL configuration tobe DL symbol and flexible symbol, respectively, this becomes a conflictcondition for the UE with regard to the UL grant-free allocation.

FIG. 7 illustrates an example manner of dealing with a conflict formini-slot repetition. In some embodiments, when less than L UL OFDMsymbols are available according to the UL-DL configuration in atransmission occasion, the UE will puncture or rate match a transmissionoccasion to transmit in available UL OFDM symbols according to the UL-DLconfiguration. In some embodiments, instead of using less than L OFDMsymbols in a first transmission occasion, a first set of available LOFDM symbols or a first set of available consecutive L OFDM symbols canbe used as the first transmission occasion. In both embodiments, for theremaining K−1 transmission occasion, each TO is the L consecutivesymbols immediately following the previous transmission occasion (as inFIG. 5). If there are conflict with the following TOs, they can also bepunctured/rate matched.

FIG. 7 shows how only OFDM symbols 6 and 7 are used from the originalgrant-free transmission occasion of OFDM symbols 4 to 7 for the firstgrant-free transmission occasion. As only two OFDM symbols are availableto the UE, the UE punctures the information of four OFDM symbols fortransmission on the two available OFDM symbols, or rate matches theinformation for four OFDM symbols for transmission on the two availableOFDM symbols.

For a scenario with K transmissions (including repetitions), once thefirst transmission has been allocated to the first transmissionoccasion, i.e. OFDM symbols 6 and 7, the remaining K−1 transmissionoccasions can be allocated in the slot and/or into subsequent slotswithin the period configured for the UL grant-free traffic. No matterhow the first TO is determined, in one embodiment, each of the remainingK−1 transmission occasions includes the L consecutive symbolsimmediately following the previous transmission occasion. If there areconflict with the following TOs, they can also be punctured/ratematched. In another embodiment, the remaining K−1 transmission occasionsmay be the L consecutive symbols that are all available UL symbolsfollowing the previous transmission occasions. In another words, if oneof the symbol is not an available UL symbol, the TO should be furthershifted later on a symbol by symbol basis until L consecutive availableUL symbols are found. In another embodiment, the remaining K−1transmission occasions may be the L symbols that are all available ULsymbols following the previous transmission occasions, however, the Lsymbols does not need to be consecutive in time domain. In anotherwords, if one symbol is not an available UL symbol for the TO, the UEcan use one available symbol later to get the L available symbols forthe transmission. The above postponing rule may also be applicable tothe first TO and may also applicable to other scenarios other than theone described in FIG. 7.

With regard to the example of FIG. 7, for the first transmissionoccasion, the UE performs puncturing to X=2 OFDM symbols. The TBS can bebased on X=2 OFDM symbols or L=4 configured OFDM symbols. If X<A (A is athreshold, e.g., A=0 or 1), the transmission occasion can be dropped oromitted, for which additional example will be described below in FIGS. 9and 10.

For each of the 2^(nd) transmission occasion and the followingtransmission occasions, the UE determines next continuous L=4 UL OFDMsymbols following previous transmission occasions. If the TBS of all therepetitions are kept the same and if the TBS of the first repetition isbased on configured L=4 OFDM symbols for grant-free resource allocation,then puncturing/rate matching can be used if the available UL symbols inthe following TOs are less than L=4. If TBS of the first transmissionoccasion determined based on available UL symbols of the firsttransmission occasion (i.e. based on X=2 OFDM symbols) then in someembodiments, the following transmission occasions are determined basedon the next continuous L=4 UL OFDM symbols following previous TOs, thenrate matching based on cyclic repetition can be performed i.e. expandX=2 OFDM symbols to available 4 OFDM symbols. In other embodiments, theTBS of the first transmission occasion and the subsequent repetitionsare based on X=2 OFDM symbols, where X is the available UL symbol forthe first transmission occasion and the following transmissionoccasions, each of which is determined based on the next continuous X ULOFDM symbols following previous transmission occasions.

FIGS. 8A, 8B and 8C illustrate examples of different ways thatboundaries may be crossed between slots to provide the K transmissionoccasions in a min-slot based repetition scheme as opposed to the onegrant-free transmission occasion per slot scheme described above withregard to the examples of FIGS. 3 to 7.

For the mini-slot repetition, the first TO may be punctured to theavailable UL symbols in conflict as in FIG. 8A or the first TO may bepostponed to the next L consecutive UL symbols, or just the next Lavailable UL symbols, where L is the configured number of OFDM symbolsfor the grant-free transmission as described for FIG. 5 and FIG. 7. Notethat FIGS. 8A, 8B and 8C only show the first TO being punctured/ratematched to the available UL symbols according to the UL-DLconfiguration, however, the same rule can be applied if the first TO ispostponed. The following up to K−1 TOs for the repetition of the same TBfor mini-slot based repetition may be based on the L symbols immediatelyfollowing the previous TO, or may be based on the next L consecutiveavailable UL symbols, or the next L available UL symbols that are notnecessarily consecutive following the previous TOs, where L is theconfigured number of symbols for grant-free transmission.

FIG. 8A shows two adjacent slots, each having 14 OFDM symbols, for atotal of 28 OFDM symbols. In FIG. 8A, it is indicated that OFDM symbols4 to 7 of the first slot were previously allocated for grant-freetransmission occasions. From the result of UL-DL configuration of slotformat, OFDM symbols 1 to 4 of the first slot are allocated for DLtraffic, OFDM symbol 5 of the first slot is allocated to be flexible,and OFDM symbols 8 to 14 of the first slot and OFDM symbols 15 to 28 ofthe second slot are allocated for UL traffic. The first UL grant-freetransmission occasion is allocated in a similar manner to FIG. 7. Thesecond UL grant-free transmission occasion is allocated as OFDM symbols8 to 11 of the first slot. The third UL grant-free transmission occasionis allocated as OFDM symbols 12 to 14 of the first slot and OFDM symbol15 of the second slot. The fourth UL grant-free transmission occasion isallocated as OFDM symbols 16 to 19 of the second slot. In this example,a transmission occasion (the third UL grant-free transmission occasionin the example of FIG. 8A) is allowed to cross a slot boundary and betransmitted on OFDM symbols in two slots.

FIG. 8B shows two adjacent slots, each having 14 OFDM symbols. In FIG.8B, the first two UL grant-free transmission occasions are allocated inthe same manner as in FIG. 8A, but the third and fourth UL grant-freetransmission occasions are allocated somewhat differently with regard tothe first slot/second slot boundary. The third UL grant-freetransmission occasion is allocated as only OFDM symbols 12 to 14 of thefirst slot. This means that there are only three OFDM symbols beingused. In such a case, rate matching or puncturing can be used whentransmitting the grant-free traffic on this transmission occasion. Thefourth UL grant-free transmission occasion is allocated as OFDM symbols15 to 18 of the second slot. In this example, a transmission occasion isnot allowed to cross a slot boundary and a transmission occasion (thethird UL grant-free transmission occasion in FIG. 8B) can use anabbreviated number of OFDM symbols by rate matching or puncturing.

FIG. 8C shows two adjacent slots, each having 14 OFDM symbols. In FIG.8C, the first two UL grant-free transmission occasions are allocated inthe same manner as in FIG. 8A, but the third and fourth UL grant-freetransmission occasions are allocated somewhat differently with regard tothe first slot/second slot boundary. The final three OFDM symbols of thefirst slot are not used as a possible transmission occasion. The thirdUL grant-free transmission occasion is allocated as OFDM symbols 15 to18 of the second slot. The fourth UL grant-free transmission occasion isallocated as OFDM symbols 19 to 12 of the second slot. In this example,a transmission occasion is not allowed to cross a slot boundary and anumber of OFDM symbols at the end of a slot may be omitted, but the nextsequential transmission occasion is not dropped, and it occurs in thestart of the next slot.

FIGS. 8A, 8B and 8C show the first TO is punctured/rate matched,however, the same example can be applicable if the first TO is alsoupdated, in case of conflict, by finding the next L availableconsecutive OFDM symbols by delaying symbol by symbol starting at theconfigured L OFDM symbols.

FIGS. 9 and 10 illustrate two additional examples of a mini-slot basedscheme. In FIG. 7, OFDM symbols 6 and 7 that were originally allocatedas a first UL grant-free transmission occasion for grant-free traffic isused for a first transmission, and subsequent transmission occasionswere allocated thereafter in the same slot. In FIG. 9, instead of usingOFDM symbols 6 and 7, those symbols, although available for UL traffic,are not used, and as a result, the originally allocated firsttransmission occasion is not used for UL grant-free traffic. The nexttransmission occasion, that is OFDM symbols 8 to 11, are allocated asthe second transmission occasion for a first repetition transmission ofa UL grant-free retransmission. The remaining transmission occasions forthe remaining repetition transmissions, up to K−2, are includedthereafter, if they fit within the period.

In FIG. 10, instead of using OFDM symbols 6 and 7, those symbols,although available for UL grant-free transmission, are not used. Thefirst transmission occasion used for a first UL grant-free transmissionis OFDM symbols 8 to 11. The remaining transmission occasions, up toK−1, are included thereafter, if they fit within the period for K−1repetition transmissions. The examples of FIGS. 9 and 10 are similar inthat they both omit the use of available UL OFDM symbols that werepreviously allocated for a first UL grant-free transmission occasion,but differ as to whether the dropped TO is not counted as one of the KTOs, where the TO is postponed (FIG. 10) and thus is not counted as oneof the K TOs, or the TO is dropped and counted as one of the K TOs sothat less than K TOs are available after dropping (as shown with respectto FIG. 9).

In a particular example, even though K, the number of repetitionsconfigured by the network, is equal to 4, only a total of 3 repetitiontransmissions can be performed for the TB, which uses the 2^(nd), 3^(rd)and 4^(th) transmission occasion of the previously allocated grant-freetransmission occasions as the updated grant-free transmission occasionsfor the actual grant-free transmission. In such an example, the indicesin the RV sequence are mapped to the actual number of repetitions thatis performed. For an RV sequence={0 2 3 1} and K=4, when the firsttransmission occasion is dropped, the first three RV sequence indices {02 3} are mapped to the three updated grant-free transmission occasions.In this example, if the UE has UL grant-free traffic that arrives beforethe first transmission occasion, the UE can only perform 3 repetitionsof the TB at in the three transmission occasions using RV sequence {0 23}, respectively. In another example, if after dropping the TO, an extraTO is used to obtain K TOs for the same TB, the RV sequence may bemapped to the new K TOs, in which case, the RV sequence is {0 2 3 1}mapped to the new TO.

In another example, when the transmission occasion is dropped/omitted,the corresponding RV index is also dropped/omitted from the RVsequence/pattern. In such an example, the RV sequence is mapped to thepreviously allocated grant-free transmission occasions (in this example,the original continuous transmission occasions). For a RV sequence {0 23 1} and K=4, when the first transmission occasion is dropped oromitted, the remaining RV sequence indices {2 3 1} are mapped to theremaining three transmission occasions, respectively.

FIG. 11 illustrates another example of a mini-slot based scheme. In someembodiments, instead of using only an available number of OFDM symbolsthat is less than L as a transmission occasion, a first set of L OFDMsymbols can be used as a transmission occasion. In the example of FIG.11, instead of using only OFDM symbols 6 and 7 from a previouslyallocated first UL grant-free transmission occasion, the firstgrant-free transmission occasion includes those two OFDM symbols, aswell as the subsequent two OFDM symbols, OFDM symbols 8 and 9, for atotal of K=4 OFDM symbols. The first UL grant-free transmission occasionis effectively shifted, or postponed, to the first available set of LOFDM symbols that have been configured for UL traffic. The nexttransmission occasion, that is OFDM symbols 10 to 13, are allocated asthe second transmission occasion for transmission of a first repetitiontransmission. The remaining transmission occasions, up to K−2, areincluded thereafter, if they fit within the period. If the new updatedtransmission occasion exceeds the current period, it may be dropped.

With reference to FIG. 11, for a 1^(st) transmission occasion, the UEdetermines the next available set of L OFDM symbols. For the 2^(nd)transmission occasion, the UE determines the next available set of LOFDM symbols. After the 1^(st) transmission occasion, if the n-thtransmission occasion has less than L UL OFDM symbols, the UE can usetransmission occasions that are consistent with the boundary conditionsof the examples described above in FIGS. 8A, 8B and 8C.

It should be understood that the manner of handling a slot boundary fortransmission occasions of grant-free repetitions subsequent to the firsttransmission, in scenarios similar to the examples of FIGS. 9 to 11, canbe similar to the examples of transmission occasions of grant-freerepetitions subsequent to the first transmission as described above withregard to FIGS. 8A, 8B and 8C.

The examples that are described below in FIGS. 3 to 7, 8A, 8B, 8C and 9to 11 are all based on UL grant-free transmission occasions having LOFDM symbols, where L is four OFDM symbols, in slots that have 14 OFDMsymbols. The number of grant-free transmission occasions K allocated ina single period is four, i.e. a first grant-free transmission and 3additional repetitions. The values of L and K, while the same,respectively, for the various examples described in the application areunderstood not to be limited by these examples.

The available number of UL OFDM symbols for a given transmissionoccasion in a particular slot may be L OFDM symbol or less depending onif there are any conflicts. In a particular example for L=4, when lessthan 4 OFDM symbols are available, the UE makes a decision as to whetherutilizing the less than four symbols for the transmission occasion, byrate matching or puncturing, or not using the less than four OFDMsymbols and awaiting the next set of four OFDM symbols in a subsequenttransmission occasion, where the next set of four OFDM symbols are for asecond or third repetition, or not using the less than four OFDM symbolsas part of a set of four OFDM symbols, but using the less than four OFDMsymbols plus additional OFDM symbols to form a set of four OFDM symbolsthat form a new first transmission occasion.

In the examples above, only the first grant-free transmission occasionwas affected by the UL-DL configuration. In this case, only thetransmission occasion with index 1 was affected. However, it is possiblethat the number of transmission occasions is different than K=4, forexample K=8, and a different number of transmission occasions, forexample, the first, second and third transmission occasions(corresponding to indices 1, 2 and 3 of the RV sequence), arereconfigured, which results in a conflict for UL grant-freetransmission.

In the examples above described with regard to FIGS. 3 to 7 and 9 to 11,it is determined how a conflict may be resolved. In some embodiments,when there are fewer UL OFDM symbols (denoted by X) available accordingto UL-DL configuration in a previously allocated first grant-freetransmission occasion than the configured L OFDM symbols, a decision hasto be made between options such as (i) use the fewer than L OFDM symbolsand rate match or puncture an UL transmission on the available X OFDMsymbols, (ii) omit the available UL OFDM symbols from the previouslyallocated first transmission occasion that are configured to be used forUL grant-free transmission, and postpone to the next previouslyallocated transmission occasion (which can be used for a first GFtransmission occasion (i.e. mapped to the first index of RV sequence) orsecond GF transmission occasion (i.e. mapped to the second index of RVsequence)), or (iii) instead of using only the fewer than L OFDM symbolsavailable from the previously allocated first transmission occasion thatare configured to be used for UL grant-free transmission, use the firstavailable L OFDM symbols as a first transmission occasion starting withan OFDM symbol that was part of a previously allocated transmissionoccasion, such that the new first transmission occasion includes OFDMsymbols that may not be completely overlap with one of the previouslyallocated grant-free transmission occasions.

The decision of whether to use any of puncturing/rate matching,postponing or dropping and how to do RV mapping to resolve the conflictmay be made in part based on one or more of the following conditions. Inone embodiment, in the case where the number X of available UL OFDMsymbols for a GF TO is less than the configured number L of symbols, butthe X available UL OFDM symbols are still enough for an UL transmission(e.g. X>A, where A is a threshold and can be 0, or 1), the decision thatwhether to do a puncturing/rate matching or dropping/postpone to resolvethe conflict may be made in part based on one or more of the followingconditions. A first condition may be the value of the index of thetransmission occasion. For example, the first GF TO that corresponds toRV0 may be more important for reliability. If it is punctured or ratematched to less than L OFDM symbols, the reliability may be compromised.Therefore, postponing or dropping for this TO may be chosen instead ofpuncturing or rate matching.

A second condition may be the RV index corresponding to the GF TO. Forexample, the GF TO corresponding to RV0 may be more important than otherRVs for the reliability. RV0 can usually be self-decodable. Therefore,in the case of available UL OFDM symbols X<the configured L symbol for aGF TO corresponding to RV0, UE can postpone the GF TO instead ofpuncturing/rate matching.

A third condition may be the values of the configured RV sequence. Thedecision may be dependent on which RV sequence is assigned. For example,UE may behave differently when the RV sequence is {0 2 3 1} than whenthe RV sequence is {0 0 0 0}.

In a particular example when the RV sequence is {0 2 3 1}, thetransmission occasions with respect to RV index “0” should not bepunctured or rate matched if there is a conflict. Alternatively, thefirst GF transmission occasion should not be punctured or rate matchedif there is a conflict (but other TO may be punctured or rate matched).In other words, for the first transmission occasion, a UE may usepostpone or dropping solution to resolve the conflict, while for othertransmission occasions, the UE may use puncturing/rate matching first ifit can be done. The transmission occasion should be maintained as Lsymbols for reliability. If the first transmission occasion has Xavailable UL OFDM symbols and X<L, where L is the configured number ofOFDM symbols for the transmission occasion, this is considered aconflict and allocation of the transmission occasion should be postponedor dropped. All the postponing solutions described in the disclosure canbe applied here. For example, in a slot based repetition scheme, the UEmay postpone the transmission occasion to the next slot or drop thetransmission occasion as described from FIG. 3A and FIG. 3B if there isconflict. The RV sequence should be mapped to the new transmissionoccasion after postpone/drop, i.e., the postponed transmission occasionis mapped to RV 0 instead of RV 2. In some other embodiments, all the RVmapping schemes described in this disclosure after postpone or droppingcan also be applied here. Note that the conflict can mean the number ofavailable UL symbols among the configured L symbols of the transmissionoccasion is less than L (as in FIG. 4) or it can mean the number ofavailable UL symbols in the slot of the transmission occasion aftershifting is less than L (as in FIG. 6) or any other conflict conditionsdescribed. For all the other transmission occasions (not the firsttransmission occasion), the UE may do puncturing/rate matching first ifthe available UL symbols is enough for a UL transmission in thetransmission occasion (e.g. X>=a threshold A (e.g., A=0, or 1)) andpostpone or drop if not enough UL symbols available for a transmission(e.g., X <A). For mini-slot based repetition, the first transmissionoccasion in conflict can be postponed to a next set of available L ULOFDM symbols or next set of available L consecutive OFDM symbols, or thenext previously allocated transmission occasion. When postponed to thenext previously allocated transmission occasion, the omittedtransmission occasion may or may not count as one of the K transmissionoccasions. When the omitted transmission is not count as one of the Ktransmission occasion, more transmission occasion can be added to obtainK transmission occasion if it is available within the period. In otherwords, the transmission occasion can be postponed as in FIG. 10 on atransmission occasion basis (postpone to the next transmission occasionof the original configured grant-free transmission occasion) or shiftedsymbol by symbol to find the next L consecutive symbols as in FIG. 11.For all other transmission occasions other than the first transmissionoccasion, the transmission occasion may be punctured/rate matched to theavailable UL symbols (e.g. X >=a threshold A (e.g., A=0, or 1)) andpostpone or drop if not enough UL symbols available for a transmission(e.g., X <A). For grant-free repetitions corresponding to the RVsequence {0 2 3 1}, the starting position of the initial transmission ofthe TB can only be on the first transmission occasion, in other words,the initial transmission of the TB can only start at the firsttransmission occasion. If the first transmission occasion is postponed,the starting position of the initial transmission can only happen at thepostponed first transmission occasion, which is still mapped to RV 0 andcan be at a different location than the originally allocated firstgrant-free transmission occasion.

If the RV sequence is {0 3 0 3}: in some embodiments, any transmissionoccasion of the K repetitions that are associated with RV index “0”should not be punctured/rate matched if there is conflict. In this case,the starting position of the initial transmission of a TB can be at anyof the transmission occasions of the K repetitions that are associatedwith RV 0 (RV=0). Alternatively, in other embodiments, only the firsttransmission occasion of the K repetitions cannot be punctured if thereis a conflict. The starting position for an initial grant-freetransmission of a TB can only be at any of the transmission occasions ofthe K repetitions that are associated with RV 0 (RV=0) that is notpunctured/rate matched. In other words, the initial transmission of a TBcan only be at a transmission occasion associated with RV 0 that usesthe full L available OFDM symbols for the transmission as configured forGF transmission. Other operation rules are similar to the rulesdescribed for RV sequence {0 2 3 1} above and are omitted here fornotational simplicity.

If the RV sequence is {0 0 0 0}, then there are various options. In someembodiments, all of the transmission occasions of the K repetitions canbe punctured. In this case, the starting position of the initialtransmission of the TB cannot be on a TO that is punctured/rate matched.For example, the starting position of the initial transmission of a TBmay be on any of the TO that is not punctured/rate matched afterresolving the conflict except the last transmission occasion when K=8.In some embodiments, the first transmission occasion of the Krepetitions should not be punctured/rate matched. In this case, thestarting position of the initial transmission of the TB cannot be on aTO that is punctured/rate matched. For example, the starting position ofthe initial transmission of a TB may be on any of the TO that is notpunctured/rate matched after resolving the conflict except the lasttransmission occasion when K=8. In some embodiments, all of thetransmission occasions should not be puncture/rate matched, and thestarting position of the initial transmission of the TB may be on any ofthe TO except the last transmission occasion when K=8.

A fourth condition may be how the RV sequence indices are mapped to theUL grant-free transmission occasions.

In some embodiments, the RV sequence is mapped to align with theoriginally allocated UL grant-free transmission occasions. If an RVsequence of {0 2 3 1} is contemplated, and if the number of availableOFDM symbols in the first TO is less than the number L of configuredOFDM symbols, all transmission occasions in a current period aredropped. If an RV of {0 3 0 3} is contemplated, and if the number X ofavailable OFDM symbols is less than L of configured OFDM symbols, for atransmission occasion associated with RV index “0”, both the TOassociated with RV “0” and following RV “3” will be dropped. If an RVsequence of {0 0 0 0} is contemplated, only previously allocatedtransmission occasions that are in conflict are omitted.

In some embodiments, if a puncturing method is adopted as shown in theexample of FIG. 5, if X<L, and it is the first transmission occasion, orbased on the RV specific puncturing criteria, the transmission occasionshould be dropped or postponed to the next slot.

In some embodiments, if shift (and puncturing) is adopted as shown inthe example of FIG. 6, if the available symbols in a slot X<L, and basedon the RV specific puncturing criteria, the transmission occasion cannotbe punctured, then the transmission occasion should be dropped orpostponed to next slot.

In the case of resolving the conflict, the UE decides whether to dopuncturing or postpone/drop/omit OFDM symbols of a transmissionoccasion, for a mini-slot or a slot based repetition, based on at leastone of the following conditions/parameters: the index of thetransmission occasion, the configured RV sequence, and the RV indexmapped to the transmission occasion.

In some embodiments, transmitting a grant-free transmission on a new setof UL resources includes at least the following operations:puncturing/rate matching the resource from the original L configuredOFDM symbols to the available X OFDM symbols not in conflict; drop thecurrent transmission occasion; postpone the transmission occasion; orpostpone the transmission occasion until the end of a slot or thegrant-free period and then puncturing or dropping.

Puncturing/rate matching may include: 1) determining a transport blocksize (TBS) and 2) rate matching to the available X UL OFDM symbols giventhe determined TBS. The TBS may be determined based on the configuredMCS and the time-frequency resources derived based on Y UL OFDM symbols.The value of Y can be L; the available X symbols in the firsttransmission occasion; or the minimum value of each of the Ktransmission occasions, i.e., min(X₁, X₂, . . . , X_(K)), where X_(i) isthe available OFDM symbols for the ith transmission occasion (1<=i<=K).The puncturing/rate matching of ith transmission occasion may furtherinclude: puncturing/rate matching if X_(i)<Y, and cyclic repetition ifX_(i)>Y.

Dropping the current transmission occasion does not affect thetransmission allocation of the following transmission occasions for thesame transmission block (TB). In some embodiments, dropping includesdropping the transmission occasion index and mapping the RV sequence tothe original configured K TOs. In some embodiments, dropping includesdropping the transmission occasion, remapping the RV sequence to the newH transmission occasions, where H<K is the number of transmissionoccasions excluding the dropped transmission occasions.

Deciding whether to postpone/drop/omit in the case of conflict mayinclude, if the transmission occasion is either a first transmissionoccasion or a transmission occasion associated with an RV sequence valueequal to “0”, performing postponing/dropping/omitting, and performingpuncturing in other cases. The starting position of an initialtransmission of K repetitions should not be in a transmission occasionthat is punctured.

Postponing the transmission occasion means the number of transmissionoccasions are not reduced after postponing, and the RV sequence ismapped to the new transmission occasion index, not the originalallocated K resources. If only a number H, where H<K transmissionoccasions can be found within a time window defined by the periodicityafter postponing, UE drop the last K−H transmission occasions.

Postponing a transmission occasion may include: postponing on an OFDMsymbol level, which involves moving the transmission occasion symbol bysymbol until no conflict occurs, i.e. a set of L available continuousavailable UL OFDM symbols; postponing on a slot level, which involvesmoving the transmission occasion slot by slot until a transmissionoccasion with no conflict is found; postponing on a transmissionoccasion level, which involves moving to the next transmission occasion,i.e. for a mini-slot with L=4 configured OFDM symbols, move to the nextavailable 4 UL OFDM symbols.

In some embodiments, when there is conflict between grant-free resourcesand control signaling and measurement, grant-free signaling may excludesymbols used for control signaling and take priority over measurementsignals.

In some embodiments, an unknown symbol may be treated as not usable forgrant-free without a DCI override. In some embodiments, a last UL symbolmay be excluded for grant-free use for uplink control information (UCI).

FIG. 12 illustrates an embodiment method involving a step 1210 ofdetermining a conflict area between a resource allocation for grant-freeuplink transmissions and one or more of: an uplink/downlink transmissiondirection configuration; a sounding reference signal configuration; oran uplink control information configuration. Step 1210 may also includedetermining that the grant-free transmission is scheduled in a resourcethat is not allocated for an UL transmission.

A further step 1220 involves performing an uplink grant-freetransmission using a selected resource for the grant-free uplinktransmission, wherein the selected resource omits the conflict area.

Step 1220 may also include determining a first available transmissionoccasion in an UL transmission resource that can be used for grant-freeuplink transmission. Step 1220 may also include determining up to K−1additional transmission occasions in the UL transmission resource.

In some embodiments, determining a first available transmission occasionand determining up to K−1 additional transmission occasions involvesomitting at least some of the K transmission occasions for use ingrant-free transmission if there are less than L OFDM symbols that areconfigured for use in the grant-free transmission available for thegrant-free transmission within a given time duration defining aperiodicity of grant-free transmission. Omitting at least some of Ktransmission occasions for grant-free transmission may involve omittingone or more of: the first available transmission occasion for grant-freetransmission; or one or more of the K−1 additional transmissionoccasions for grant-free transmission.

In some embodiments, when a number X of available OFDM symbols in one ofthe K transmission occasions, wherein X is an integer value >1, is lessthan a threshold of OFDM symbols that can be used for a grant-freeallocation, selecting a new first available transmission occasion in theUL that has a number of OFDM symbols that is greater than the thresholdof OFDM symbols.

In some embodiments, when a number X of available OFDM symbols in one ofthe K transmission occasions, wherein X is an integer value >1, isgreater than a threshold of OFDM symbols that can be used for agrant-free allocation, but less than a number L of configured OFDMsymbols for the one of the K transmission occasions, wherein L is aninteger value >1, using rate matching when transmitting on the one ofthe K transmission occasions allocated for grant-free transmission. Ratematching may include one of puncturing or cyclic repetition of the XOFDM symbols in the L configured OFDM symbols for the grant-freetransmission.

In some embodiments, a number of Y OFDM symbols used to define atransport block size for each of the K transmission occasions is equalto (i) a number of available OFDM symbols in the first availabletransmission occasion, or (ii) a minimum number of available OFDMsymbols in any of the first available transmission occasion and the K−1additional transmission occasions.

FIG. 13 illustrates a diagram of an embodiment method 1300 for wirelesscommunications. The method 1400 may be indicative of operations at a UE.As shown, at step 1310, the UE determines that a transmission resourceincludes a first orthogonal frequency-division multiplexing (OFDM)symbol that is configured as a downlink symbol or as flexible. Thetransmission resource is allocated for uplink (UL) transmissions duringa time duration, and includes K transmission occasions (TOs), where K isan integer greater than 1. At step 1320, the UE transmits a first ULtransmission in the transmission resource omitting the first OFDMsymbol. The first UL transmission includes K repetitions to betransmitted in the respective K TOs, and the K repetitions includes aninitial transmission and at least one retransmission of the initialtransmission.

FIG. 14 is a block diagram of a computing system 1400 that may be usedfor implementing the devices and methods disclosed herein. For example,the computing system can be any entity of a UE, access node (AN), MM,SM, UPGW, AS. Specific devices may utilize all of the components shownor only a subset of the components, and levels of integration may varyfrom device to device. Furthermore, a device may contain multipleinstances of a component, such as multiple processing units, processors,memories, transmitters, receivers, etc. The computing system 1400includes a processing unit 1402. The processing unit includes a centralprocessing unit (CPU) 1402, memory 1408, and may further include a massstorage device 1404, a video adapter 141o, and an I/O interface 1412connected to a bus 1420.

The bus 1420 may be one or more of any type of several bus architecturesincluding a memory bus or memory controller, a peripheral bus, or avideo bus. The CPU 1402 may comprise any type of electronic dataprocessor. The memory 1408 may comprise any type of non-transitorysystem memory such as static random access memory (SRAM), dynamic randomaccess memory (DRAM), synchronous DRAM (SDRAM), read-only memory (ROM),or a combination thereof. In an embodiment, the memory 1408 may includeROM for use at boot-up, and DRAM for program and data storage for usewhile executing programs.

The mass storage 1404 may comprise any type of non-transitory storagedevice configured to store data, programs, and other information and tomake the data, programs, and other information accessible via the bus1420. The mass storage 1404 may comprise, for example, one or more of asolid state drive, hard disk drive, a magnetic disk drive, or an opticaldisk drive.

The video adapter 1410 and the I/O interface 1412 provide interfaces tocouple external input and output devices to the processing unit 1402. Asillustrated, examples of input and output devices include a display 1418coupled to the video adapter 1410 and a mouse/keyboard/printer 1416coupled to the I/O interface 1412. Other devices may be coupled to theprocessing unit 1402, and additional or fewer interface cards may beutilized. For example, a serial interface such as Universal Serial Bus(USB) (not shown) may be used to provide an interface for an externaldevice.

The processing unit 1402 also includes one or more network interfaces1406, which may comprise wired links, such as an Ethernet cable, and/orwireless links to access nodes or different networks. The networkinterfaces 1406 allow the processing unit 1402 to communicate withremote units via the networks. For example, the network interfaces 1406may provide wireless communication via one or more transmitters/transmitantennas and one or more receivers/receive antennas. In an embodiment,the processing unit 1402 is coupled to a local-area network 1422 or awide-area network for data processing and communications with remotedevices, such as other processing units, the Internet, or remote storagefacilities.

The following embodiments are also provided.

In accordance with an embodiment of the present disclosure, there isprovided a method for grant-free uplink transmission, the methodcomprising: determining a conflict area between a resource allocationfor grant-free uplink transmissions and: an uplink/downlink transmissiondirection configuration; a sounding reference signal configuration; oran uplink control information configuration; and performing an uplinkgrant-free transmission using a selected resource for the grant-freeuplink transmission, wherein the selected resource omits the conflictarea.

In some embodiments, determining the conflict area comprises determiningthat the grant-free transmission is scheduled in a resource that is notallocated for an UL transmission.

In some embodiments, performing the uplink grant-free uplinktransmission comprises determining a first available transmissionoccasion in an UL transmission resource that can be used for grant-freeuplink transmission.

In some embodiments, the method further comprises determining up to K−1additional transmission occasions in the UL transmission resource.

In some embodiments, the K−1 additional transmission occasions aredetermined on a one transmission occasion per slot basis, wherein a slotincludes M orthogonal frequency division multiplexed (OFDM) symbols,wherein M is an integer value >1, and each transmission occasionincludes up to L OFDM symbols, wherein L is an integer value >1.

In some embodiments, the K−1 additional transmission occasions aredetermined on a more than one transmission occasion per slot basis,wherein a slot includes M OFDM symbols, wherein M is an integervalue >1, and each transmission occasion includes up to L OFDM symbols,wherein L is an integer value >1.

In some embodiments, determining a first available transmission occasionand determining up to K−1 additional transmission occasions comprises:omitting at least some of the K transmission occasions for use ingrant-free transmission if there are less than L OFDM symbols that areconfigured for use in the grant-free transmission available for thegrant-free transmission within a given time duration defining aperiodicity of grant-free transmission.

In some embodiments, omitting at least some of K transmission occasionsfor grant-free transmission comprises omitting one or more of: the firstavailable transmission occasion for grant-free transmission; or one ormore of the K−1 additional transmission occasions for grant-freetransmission.

In some embodiments, the method further comprises: when a number X ofavailable OFDM symbols in one of the K transmission occasions, wherein Xis an integer value >1, is less than a threshold of OFDM symbols thatcan be used for a grant-free allocation, selecting a new first availabletransmission occasion in the UL that has a number of OFDM symbols thatis greater than the threshold of OFDM symbols.

In some embodiments, the method of further comprises, when a number X ofavailable OFDM symbols in one of the K transmission occasions, wherein Xis an integer value >1, is greater than a threshold of OFDM symbols thatcan be used for a grant-free allocation, but less than a number L ofconfigured OFDM symbols for the one of the K transmission occasions,wherein L is an integer value >1, using rate matching when transmittingon the one of the K transmission occasions allocated for grant-freetransmission.

In some embodiments, rate matching includes one of puncturing or cyclicrepetition of the X OFDM symbols in the L configured OFDM symbols forthe grant-free transmission.

In some embodiments, a number of Y OFDM symbols used to define atransport block size for each of the K transmission occasions is equalto (i) a number of available OFDM symbols in the first availabletransmission occasion or (ii) a minimum number of available OFDM symbolsin any of the first available transmission occasion and the K−1additional transmission occasions.

In some embodiments, a redundancy version (RV) sequence mapped to Ktransmission occasions is modified when less than K transmissionoccasions are allocated for grant-free transmission.

In some embodiments, when less than K transmission occasions areallocated for grant-free transmission, aligning a mapping of K−J indicesof the RV sequence, wherein J equals the number of transmissionoccasions less than K, with the K−J transmission occasions.

In some embodiments, aligning the mapping comprises: omitting one ormore transmission occasions at the beginning of a period and omittingcorresponding RV sequence indices based on an ordered mapping betweentransmission occasions and RV sequence indices; or omitting one or moretransmission occasions at the beginning of a period and maintaining amapping of the RV sequence indices in order despite omitting the RVsequence indices.

In some embodiments, the RV sequence is one of: {0,2,3,1}; {0,3,0,3}; or{0,0,0,0}.

In some embodiments, for a given slot, when a transmission occasion ofthe K transmission occasions has less than L OFDM symbols available tobe allocated in the given slot, performing the uplink grant-freetransmission in a subsequent slot.

In some embodiments, for a given slot, when a transmission occasion ofthe K transmission occasions has less than L OFDM symbols available tobe allocated in the slot, allocating the less than L OFDM symbols forthe transmission occasion in the given slot and allocating anyadditional of the K transmission occasions in a subsequent slot.

In some embodiments, performing an uplink grant-free transmission usinga selected resource for the grant-free uplink transmission comprisesdetermining whether to perform: puncturing of a transmission to transmiton a number of available OFDM symbols that is less than a number ofallocated OFDM symbols; or postponing a transmission by omitting OFDMsymbols and as a result transmit on a number of available OFDM symbolsthat is equal to a number of allocated OFDM symbols.

In some embodiments, determining whether to perform puncturing of atransmission or postponing a transmission by omitting OFDM symbols isbased on at least one of: an index of the transmission occasion, thevalues of a configured redundancy version (RV) sequence; and manner inwhich the RV index is mapped to a transmission occasion.

In accordance with an embodiment of the present disclosure, there isprovided an user equipment (UE) configured for grant free transmissions,the UE comprising: a processor; and a computer readable storage mediumstoring programming instructions for execution by the processor, theprogramming including instructions to: determining a conflict areabetween a resource allocation for grant-free uplink transmissions and:an uplink/downlink transmission direction configuration; a soundingreference signal configuration; or an uplink control informationconfiguration; and performing an uplink grant-free transmission using aselected resource for the grant-free uplink transmission, wherein theselected resource omits the conflict area. The UE may be configured toperform other embodiments as described above.

In accordance with an embodiment of the present disclosure, there isprovided a method for grant-free uplink transmission, the methodcomprising: determining a conflict area between a resource allocationfor grant-free uplink transmissions and: an uplink/downlink transmissiondirection configuration; a sounding reference signal configuration; oran uplink control information configuration; and receiving an uplinkgrant-free transmission using a selected resource for the grant-freeuplink transmission, wherein the selected resource omits the conflictarea.

In accordance with an embodiment of the present disclosure, there isprovided a base station configured for grant free transmissions, thebase station comprising: a processor; and a computer readable storagemedium storing programming instructions for execution by the processor,the programming including instructions to: determining a conflict areabetween a resource allocation for grant-free uplink transmissions and:an uplink/downlink transmission direction configuration; a soundingreference signal configuration; or an uplink control informationconfiguration; and receiving an uplink grant-free transmission using aselected resource for the grant-free uplink transmission, wherein theselected resource omits the conflict area.

It should be appreciated that one or more steps of the embodimentmethods provided herein may be performed by corresponding units ormodules. For example, a signal may be transmitted by a transmitting unitor a transmitting module. A signal may be received by a receiving unitor a receiving module. A signal may be processed by a processing unit ora processing module. Other steps may be performed by a determiningunit/module, a mapping unit/module, a re-mapping unit/module, apuncturing unit/module, a rate matching unit/module, a droppingunit/module, an omitting unit/module, a shifting unit/module, apostponing unit/module, and other performing unit/module for performingthe step of the above step. The respective units/modules may behardware, software, or a combination thereof. For instance, one or moreof the units/modules may be an integrated circuit, such as fieldprogrammable gate arrays (FPGAs) or application-specific integratedcircuits (ASICs).

While this disclosure has been described with reference to illustrativeembodiments, this description is not intended to be construed in alimiting sense. Various modifications and combinations of theillustrative embodiments, as well as other embodiments of thedisclosure, will be apparent to persons skilled in the art uponreference to the description. It is therefore intended that the appendedclaims encompass any such modifications or embodiments.

What is claimed is:
 1. A method for wireless communications, comprising:determining, by a user equipment (UE), that a transmission resourceincludes a first orthogonal frequency-division multiplexing (OFDM)symbol that is configured as a downlink symbol or as flexible, whereinthe transmission resource is allocated for uplink (UL) transmissionsduring a time duration, and comprises K transmission occasions (TOs), Kbeing an integer greater than 1; and transmitting, by the UE, a first ULtransmission in the transmission resource omitting the first OFDMsymbol; and wherein the first UL transmission comprises K repetitions tobe transmitted in the respective K TOs, and the K repetitions comprisesan initial transmission and at least one retransmission of the initialtransmission.
 2. The method of claim 1, wherein the first OFDM symbol issemi-statically configured for a downlink (DL) transmission.
 3. Themethod of claim 1, wherein the first OFDM symbol is semi-staticallyconfigured as flexible and dynamically configured as flexible.
 4. Themethod of claim 1, wherein the first OFDM symbol is semi-staticallyconfigured as flexible and dynamically configured for DL transmission.5. The method of claim 1, wherein the first OFDM symbol issemi-statically configured by a higher-layer parameter comprising a timedivision duplex (TDD) UL-DL configuration common parameter or TDD UL-DLconfiguration dedicated parameter.
 6. The method of claim 1, wherein theK TOs are located in K respective slots.
 7. The method of claim 1,wherein transmitting the first UL transmission in the transmissionresource omitting the first OFDM symbol comprises: transmitting, by theUE, the first UL transmission in the transmission resource omitting afirst TO of the K TOs that comprises the first OFDM symbol.
 8. Themethod of claim 7, wherein the first TO is omitted upon determining thatthe first TO has less than a threshold number of OFDM symbols that areavailable for UL transmissions.
 9. The method of claim 7, wherein thefirst TO is omitted upon determining that the first TO is not configuredfor the initial transmission.
 10. The method of claim 7, wherein thefirst TO is omitted upon determining that the first TO is not associatedwith a specific redundant version (RV) index.
 11. The method of claim 7,wherein transmitting the first UL transmission in the transmissionresource omitting the first TO comprises: transmitting, by the UE in asecond TO that is subsequent to the first TO comprising the first OFDMsymbol, a first repetition of the K repetitions that is corresponding tothe first TO.
 12. The method of claim 11, wherein the first TO and thesecond TO are in different slots.
 13. The method of claim 7, whereintransmitting the first UL transmission in the transmission resourceomitting the first TO comprises: transmitting, by the UE, less than Krepetitions in the transmission resource during the time duration. 14.The method of claim 13, further comprising: re-mapping a redundantversion (RV) sequence associated with the K TOs to the less than Krepetitions, the RV sequence comprising a plurality of RV indices. 15.The method of claim 7, wherein transmitting the first UL transmission inthe transmission resource omitting the first TO comprises: transmitting,by the UE, the K repetitions during the time duration, at least onerepetition being transmitted in an OFDM symbol that is subsequent to theK TOs.
 16. The method of claim 1, wherein transmitting the first ULtransmission in the transmission resource omitting the first OFDM symbolcomprises: transmitting, by the UE, a repetition in OFDM symbols of afirst TO that comprises the first OFDM symbol, omitting the first OFDMsymbol.
 17. The method of claim 16, further comprising: puncturing, bythe UE, the repetition for transmitting the repetition in the OFDMsymbols of the first TO.
 18. The method of claim i6, further comprising:performing, by the UE, rate matching on the repetition for transmittingthe repetition in the OFDM symbols of the first TO.
 19. The method ofclaim 16, wherein transmitting the repetition further comprises:transmitting, by the UE, the repetition in a set of OFDM symbolssubsequent to the first OFDM symbol, the set of OFDM symbols beingavailable for UL transmissions.
 20. The method of claim 19, wherein theset of OFDM symbols comprises consecutive OFDM symbols.
 21. The methodof claim 1, wherein the K TOs are associated with a redundant version(RV) sequence comprising a plurality of RV indices, each TO being mappedto a RV index of the plurality of RV indices.
 22. A user equipment (UE),comprising: a non-transitory memory storage comprising instructions; andone or more processors in communication with the memory storage, whereinthe one or more processors execute the instructions to: determine that atransmission resource includes a first orthogonal frequency-divisionmultiplexing (OFDM) symbol that is configured as a downlink symbol or asflexible, wherein the transmission resource is allocated for uplink (UL)transmissions during a time duration, and comprises K transmissionoccasions (TOs), K being an integer greater than 1; and transmit a firstUL transmission in the transmission resource omitting the first OFDMsymbol; and wherein the first UL transmission comprises K repetitions tobe transmitted in the respective K TOs, and the K repetitions comprisesan initial transmission and at least one retransmission of the initialtransmission.
 23. The UE of claim 22, wherein the first OFDM symbol issemi-statically configured for downlink (DL) transmission.
 24. The UE ofclaim 22, wherein the first OFDM symbol is semi-statically configured asflexible and dynamically configured as flexible.
 25. The UE of claim 22,wherein the first OFDM symbol is semi-statically configured as flexibleand dynamically configured for DL transmission.
 26. The UE of claim 22,wherein the first OFDM symbol is semi-statically configured by ahigher-layer parameter comprising a time division duplex (TDD) UL-DLconfiguration common parameter or TDD UL-DL configuration dedicatedparameter.